Chemistry Course Outline

Ed RayThe following is a possible chemistry course sequence based on the NC State competency goals used for the accompanying lesson plans indicates below a state exam reference table

Introduction to Chemistry and Matter 1 Major areas of chemistry2 Matter classifications and states3 Introduction to elements and compounds and their symbolsformulas4 Physical and chemical change5 Indications of a chemical change (reaction)6 Reactants and products7 Law of conservation of mass

Scientific Measurement (CHEM ASAP C-D ROM Ch 3)1 Scientific notation2 Accuracy precision and percent error3 Significant figures in measurement and their calculations4 SI units5 Density6 Temperature scales7 Identifying substances using their physical properties(CHEM ASAP C-D ROM Ch 4 omit Section 43 omit Practice Problems 23 and 25) 8 Conversion factors dimensional analysis

Atomic Structure (CHEM ASAP C-D ROM Ch 5 omit Section 54)1 The atom its structure and isotopes-Dalton Thomson Rutherford Millikan2 Calculation of average atomic mass(CHEM ASAP C-D ROM Ch 28)3 A brief view of nuclear chemistry4 Uranium disintegration series

Arrangement of Electrons in Atoms (CHEM ASAP C-D ROM Ch 13)1 Introduction to the electromagnetic spectrum (light)2 The Bohr model and the hydrogen spectrum3 Schrondinger and the wave mechanical model of the atom4 Quantum numbers5 The electron configuration orbital notation and electron dot notation of an element

The Periodic Table and Periodicity (CHEM ASAP C-D ROM Ch 5 Section 54 only and Ch 24)

1 History divisions and blocks of the periodic table2 Relation of electron configuration to periodic table(CHEM ASAP C-D ROM 14)

3 Periodic properties-atomic and ionic radius ionization energy electron affinity and electronegativity

Ionic and Covalent Bonding (CHEM ASAP C-D ROM Ch15 and Ch 16)1 Ionic and covalent bonding2 Properties of ionic and covalent compounds3 The Lewis structure resonance VSEPR theory hybridization4 Electronegativity difference bond polarity and intermolecular forces5 Molecular polarity6 The metallic bond

Chemical Quantities Names Formulas (CHEM ASAP C-D ROM Ch 7)1 Gram atomic mass and molar mass (gmm and gfm)2 mole-mass-representative particles-volume (at STP) conversions3 Percent composition4 Empirical and molecular formulas(CHEM ASAP C-D ROM Ch 6)5 Writing formulas for and the naming of binary and ternary compounds

Chemical Reactions (CHEM ASAP C-D ROM Ch 8 omit Section 83 and omit Practice Problems 25 and 26)

1 Balancing chemical equations2 Classification of the 5 types of reactions 3 Predicting whether a reaction will take place using solubility rules-also recognizing water or a gas forms-for double replacement reactions and using an activity series for single replacement reactions4 Writing equations for all 5 types-word and formula some phase symbols use

2 Types of Solution Reactions (Precipitation Acid-Base) and Oxidation-Reduction (CHEM ASAP C-D ROM Ch 18 omit Sections 182 184 and omit Practice Problems 2 12 15 31 and 33)

1 The solution process and terms2 Solubility vs temperature curve3 Strong weak electrolytes and dissociation4 Concentrations of solution -molarity 5 Moles of solution (M X V)6 Net ionic equations of Precipitation and Acid-Base reactions (CHEM ASAP C-D ROM Ch 8 Section 83 only Practice Problems 25 and 26)7 Redox Reactions-Oxidizing and reducing agents (CHEM ASAP C-D ROM Ch 22)8 Standard reduction potential table

9 Voltaic cells standard cell potentials (CHEM ASAP C-D ROM Ch 23)

Stoichiometry (CHEM ASAP C-D ROM Ch 9)1 Mole mass and volume calculations2 Limiting reactants3 Theoretical and percent yield4 Thermochemical equations

States of Matter (CHEM ASAP C-D ROM Ch 10)1 The nature of solids liquids and gases2 Changes of state ice-water and water-vapor equilibrium3 Phase diagram

Gas Laws (CHEM ASAP C-D ROM Ch 12)1 Kinetic Molecular Theory of gases2 Real and ideal gases3 Gas laws4 Revisit gas stoichiometry5 Effusion and diffusion

Thermochemistry (CHEM ASAP C-D ROM Ch 11 omit Practice Problems 25 and 30 and Simulation 8)

1 Heat vs temperature2 Calorimetry2 Revisit thermochemistry equations4 The heating and cooling curve for water (q = mcp∆T and q = mHfus)

Reaction Rates (CHEM ASAP C-D ROM Ch 19 only Animation 22 and only Simulation 23 and 25 Skip Sections 192 and 195 and omit Practice Problems 25 27 and 29)

1 Factors affecting reaction rates2 Energy profile diagrams and collision theory3 Enthalpy entropy and free energy

Chemical Equilibrium (CHEM ASAP C-D ROM Ch 19 only Animation 23 Section 192 and Simulation 24 Practice Problems 7 8 and 12)

1 The nature of equilibrium2 The equilibrium position3 Le Chatelierrsquos principle and stresses on equilibrium4 Homogenous and heterogeneous equilibrium expressions involving

a gas c acid-baseb aqueous d solubility

5 Equilibrium constant calculations involving gasses

Acids and Bases (CHEM ASAP C-D ROM Ch 20 and Ch 21 omit Section 211 only do Practice problem 1 and 4)

1 Characteristics and indicators2 Strengths and degree of dissociation3 pH and pOH 4 Acid-base theories and buffers5 Anhydrides and acid rain6 Titration and neutralization

The following lesson plansactivities are based on the above Chemistry Course Sequence which is based on the NCDPI State competency goals This outline of lesson plans was chosen for easy access by the chemistry teacher on the GCS intranet Topics are used which allow the teacher to immediately identify where the state goals are found in the text Possible chapter topics are listed and related to state goals Finding and downloading a lesson plan for a goal using the sequence outline is straight forward Spacing between questions etc is given so that teachers can just cut and paste There is no need to match State goals and text chapters to find the activities needed Notice All lesson plans that involve CD-ROM Resources are included within the Chemistry Course Sequence above to prevent ldquoredundant citingrdquo These lessons plans included are in no way intended to be comprehensive in covering all the goals

______________________________________________________________________________Introduction to Chemistry and Matter State goal 205

Lesson plan 1 Objective

In this experiment you will mix different solutions combine solids with solutions record your observations and determine by recognizing whether a chemical change took place by writing YES (a Rxn) or NO (no Rxn) on the data sheet provided

Pre-Laboratory Name ________________________Recognizing a Chemical Change

1 What is the objective of this experiment

2 What are the 4 indicators of a chemical change

3 One milliliter of solution is approximately equal to how many drops

4 What 3 solutions are toxic and corrosive Which substance is flammable

5 Briefly describe the meaning of each of these phrases as it pertains to this experiment

a) the solution turned blue but remained clear

b) the reaction was endothermic

c) a precipitate formed

d) fizzing occurred6 Determine which of the following observations are chemical changes and which are

physical changes

a) On a hot day after a rain water turns into a water vapor

b) On a hot day water collects outside a glass holding iced tea

c) Water is added to a glass of tea and the color lightens

d) Clear colorless lemon juice is added to a glass of tea The tea color changes from brown to yellow-brown

Recognizing a Chemical Change

A chemical change occurs when a chemical substance is altered by a chemical reaction something new is formed A physical change occurs in a change of phase (melting vaporization sublimation etc) occurs in a subdivision change (chip tear grind etc) and occurs in dissolving

Such indicators are not always proof of a chemical change For example a gas can form as a result of change in physical state In a laboratory we must carefully determine which changes are connected to chemical changes and which changes are connected to physical changes

How can you tell whether a chemical change (reaction) has taken place In general there are 4 indicators

1) a temperature change (the giving off or absorption of heat by a system)2) a precipitate forms (solid forms when two aqueous solutions are mixed)3) a color change that is simply not a dilution4) a gas forms (bubbles seen and sometimes an odor)

Temperature change Every chemical reaction involves some energy transfer and in many cases the energy transfer involves easily detectible heat If a system (reaction mixture) loses heat it is termed an endothermic reaction If a reaction system gains heat it is termed an endothermic reaction

CAUTION In this investigation you may have to use a thermometer to determine a few degrees change in temperature if you cannot determine by feeling the temperature change Therefore before you indicate No Reaction you should repeat your result with a thermometer placed in the solutions during the reaction Observe any small change in temperature

Precipitate forms In many reactions a solid forms because one or more of the products is insoluble in the reaction mixture The insoluble product settles to the bottom of the test tube The insoluble substance at first appears as a cloudy suspension and slowly if ever settles to the bottom

Color change Color changes that are indicative of a chemical change sometimes result from when the chemical forms of a compound changes Example HCl an acid added to blue litmus paper turns the paper red This is because the chemical form of litmus changes In the presence of an acid the chemical form of litmus is red in color The chemical form of litmus is blue in base

Gas forms If one or more of the products is a gas at the reaction temperature bubbles form Also it is possible to identify a gas by odor by color or by other recognizable chemical properties

Safety Message NH3 HCl and NaOH solutions are toxic and corrosive Avoid contact with eyes Ethanol (C2H5OH) is flammable Wear apron and gogglesIf you spill any solution notify the teacher

In each of the following 12 experiments1) record your observations and2) indicate whether a chemical change occurred by YES or NO on the data sheet

1 mL of solution = 20 drops of solution

Exp 1 Obtain a pea size of CoC126H20 with a dry spatula and place it in a dry test tube Add 2 mL of 95 C2H5OH (ethanol) Change occurred on the data sheet

Exp 2 Transfer a piece of Zn to a test tube Add mL of 1M HC1

Exp 3 Transfer a piece of Zn to a test tube Add 2 mL of 01M CuSO4 solution

Exp 4 Use a dry graduate cylinder transfer 1 mL of 01 M CoC126H2O dissolved in 95 C2H5OH Add 1 mL of water to the solution

Exp 5 Transfer 1 mL of 01 M CuSO4 solution to a test tube Add 1 mL of 10 M HC1

Exp 6 Transfer 1 mL of O1 M CuSO4 solution to a test tube Add 1 mL of 1M NH3 solution

Exp 7 Transfer 1 mL of 01 M CuSO4 solution to a test tube Add 1 mL of 05M

NaHCO3 solution

Exp 8 Transfer a shiny 1 cm strip of Mg to a test tube Add 2 mL of 01 M CuSO4

solution

Exp 9 Transfer a shiny 1 cm strip of Mg to a test tube Add 2 mL of 1 M HC1

Exp 10 Transfer 1 mL of 1 M HC1 to a test tube Add 1 M NaOH

Exp 11 Transfer 1 mL of 1 M HC1 to a test tube Add 1 mL of 05 M NaHCO3

solution

Exp 12 Transfer a pea size of NH4C1 solid to a test tube Add 2 mL of water at room temperature

Data Sheet Name________________________Observations Did a chemical

change occur (YES or NO)

Lesson plan 2

Law of Definite Composition Objective Students will be able to

1 Observe a chemical reaction2 Calculate a ratio of mass of magnesium to mass of oxygen

Materials

Crucible and lid Tongs for crucible Safety goggles Medicine dropper Ring stand with ring Bunsen burner and lighter Scout II Balance Pipe-stem triangle Wire gauze Sandpaper Laboratory apron Magnesium ribbon Distilled water

Procedure

1 Before you start any lab with chemicals always wear your lab apron and safety goggles

2 Obtain a piece of magnesium from your instructor If it is not shiny use the sandpaper on it until it is shiny

3 Obtain a clean dry crucible and weigh it with the cover Record this mass4 Roll the magnesium in a coil and place it into the crucible Record the mass of the

crucible and the coil Subtract this mass from the mass of the crucible by itself This is the mass of the magnesium

5 Set up the ring stand assembly with the bunsen burner on the base Put the appropriate size ring just above the burner Place the pipestem triangle on the ring Now place the crucible on the pipstem triangle

6 With the lid on the crucible begin heating slowly If a large amount of smoke starts to come out of the crucible remove the heat temporarily

7 After heating for about 3-4 minutes with no smoke slightly remove the lid of the crucible Now heat the crucible to redness for about 4 minutes Finally remove the lid completely and heat strongly for four more minutes

8 Turn the burner off and put the lid back on the crucible Allow the crucible and the cover to cool to a temperature low enough so that you can touch the crucible Find the mass of the crucible contents and cover Record these masses

9 Add ten drops of the distilled water Notice any odor (smell cautiously) Set the crucible up for heating again Reheat with the lid on for four more minutes Let the crucible and lid cool again

10 Find the mass of the crucible cover and product Record your results11 Compare the masses found in steps 8 and 9 If the masses do not agree within 005 g

reheat the crucible for four minutes cool and find the mass Repeat until the last two agree within this range

12 Clean up the lab and wash your hands Follow-up questions1 What were your findings How did the masses compare before the distilled water and after2 Did you have any smoke form Why did it form 3 What was the mass of the oxygen that combined with the magnesium How do you know

Lesson plan 2 (This plan is placed at the beginning of the course it allows students to recognize a reaction early)

Rusting as a Chemical Reaction Objective Students will be able to observe which conditions are most conducive to the rusting of iron The formula for rust is Fe2O3 Materials

Eight iron nails (about 2-3 inches each) Two pairs of pliers Scissors Copper wire Zinc strip Fine grade sandpaper Plastic wrap Water Paper towels Petroleum jelly Saucer

Procedure1 With the sandpaper shine seven of the eight nails and then wipe them clean2 Trim two paper towels to fit the saucer then wet them with water3 Treat the nails as follows Nail 1 Wrap one end with copper wire Nail 2 Wrap one

end with a strip of zinc Nail 3 Bend into a ldquoUrdquo with the two sets of pliers Nail 4 Smear the whole nail with petroleum jelly Nail 5 Cover with salt after completing the next step below Nail 6 This is your unsanded untreated nail Nail 7 Leave untreated Nail 8 Leave untreated

4 Place nails 1-7 on the moistened paper towel Make sure the nails do not touch and cover them with a piece of plastic wrap Place nail 8 (the control) on top of the wrap

5 Make a table and periodically record your observations and changes in each nail over a 24 hour period

Follow-up questions1 Which nails did you observe to have the most dramatic changes (rusting) 2 Why did these nails rust more than the others3 Which nails did you notice were not rusted Why4 How can this information be used by new car manufacturers5 Write and balance the synthesis reaction for the rusting of iron

______________________________________________________________________________

Scientific MeasurementState goal 104

Lesson plan 1

Objective to acquaint students with the State Exam Reference TableStudents are to use the NC State Exam Reference Table at the beginning of the course to find information and make inferences

1 Which compound has the higher melting point sucrose (table sugar) or sodium chloride(table salt) What are the melting points of each in Kelvin in Celsius Are higher melting points more common to ionic compounds or to covalent compounds

2 A student calculated the density of silver to be 103 gcm3 Compare this answer to the accepted value What is the accepted value

3 Calculate the volume (in cm3) of gold which has a mass of 103 g

4 Ethanol (ethyl alcohol) is drinking alcohol What is the formula What is the formula of ammonia What is the formula for sodium bicarbonate (baking soda)

5 What is the International System of Units for mass temperature the amount of a substance volume

6 Calculate the mass of 224 L of carbon monoxide

7 What is the boiling point of nitrogen gas in Kelvin in Celsius

8 What is the density of water What is the density of gold Why would gold sink in water and many woods float

Lesson plan 2Significant FiguresObjective 1 To determine the appropriate number of significant figures in the result of a calculation 2 To round answers to the correct number of significant figures

1 456m X 14m =

2 1211g + 180g + 1013g =

3 650g 12cm3 =

4 55003Kg - 25 50Kg =

The following are formulas that you will encounter on the State EOC and in class The formulas are found in your Chemistry Reference Table Perform the indicated operations using the correct number of significant figures Donrsquot forget units

1 D = mV m = 105g and V= 22 L D = Answer_____________

2 D = 79 gcm3 m = 57g V = Answer_____________

3 PV = nRT P = 1002atm V = 123L R = 008206 L-atm mol-K T = 29815K n = Answer_____________

4 Q = mc∆T m = 250g c = 4184 J (g-OC) ∆T = 55ordmC Q = Answer_____________

5 V1P1 T1 = V2P2 T2 V1 = 200L P1 = 765torr T1 = 270K V2 = 25L P2 = 705torr T2 = Answer_____________

6 pH = - log[H+] Significant figures for a log The rule is that the number of decimal places in a log is equal to the number of significant figures in the original number

a Calculate the pH if the [H+] is 10 X 10-7 M There are 2 sig figures here (namely 10) so consequently your answer must show two decimal places

Answer____________b Calculate the pH if the [H+] is 255 X 10-9 M

Answer____________

Lesson plan 3Objective to determine the density of regular and irregular objects

Density Lab

Introduction An object made of cork feels lighter than an object made of lead What you are Actually comparing in this case is how massive objects are compared to their size This property is known as density Density is expressed mathematically as the ratio of mass to volume

Density = massvolume

The unit of density is often gmL 1 mL = 1 cm3

Density is a useful number in determining what a substance is Gold has a density of 19 gmL an average rock has the density of 3 gmL woods have varying densities many woods are less than 1 gmL and water has a density of 1 gmL Any substance with a density of less than water will float on water a greater density than water will sink in water

Objective In this investigation you will find the density of a liquid and two solids Masses willbe measured on a balance The volumes will be either calculated by a formula given or measured by submerging in water commonly called the Archimedes method

Donrsquot forget when reading the graduate cylinder to read the bottom of the meniscus as shown below

Procedure Liquid Place a 10 mL graduate cylinder on a balance and record its mass Remove from the balance Put exactly 10 mL (100 mL exactly) of the unknown liquid into the cylinder and find its mass again that is cylinder plus the unknown liquid

Solid (regular shape) Find the volume of the wooden cylinder by measuring the diameter and height to the nearest 01 cm (such as 25 cm) Use the formula for a cylinder V = frac14πr2h Measure the mass of a wooden cylinder

Solid (irregular object) First measure the mass of the irregular shaped object Put approximately 50 mL of water into 100 mL graduate cylinder and record the exact amount of water to the nearest decimal place in your data table (example 498 or 501) Gently place the irregular shaped object into the cylinder and record the new volume to the nearest decimal place

Pre-Lab Questions

1 Which is less dense a marshmallow or hot chocolateA) It depends on how much you haveB) The marshmallow because it floatsC) The hot chocolate because it is a liquidD) The marshmallow because it weighs 25 g and the chocolate powder weighs only 17g

2 Which is more dense water or oil

3 What mass does 30 mL of gold have

4 Calculate the volume displaced by an average rock which has a mass of 12 g

Post-Lab Questions

1 Examine the State Reference tables and discern what liquid was used in this investigation and calculate your error

2 If oil has a density of 088 gmL would it float on the liquid used in this lab

3 Since measuring the volume (actually mass and using the density formula) on a balance is more accurate than measuring the volume by reading a meniscus on a graduate cylinder densities are found differently when a more accurate answer is needed For example A cylinder completely full of water is put on a balance and then an object is submerged allowing some water to spill out Then the cylinder object and water (minus the spillover) are weighed The volume of the object is then calculated accurately Use the following data determined by the above method to find the density of the unknown object Assumethe density of water at room temperature (22ordmC) to be 09978 gmL (The density of water

at 4ordmC is exactly 1000 gmL)

Mass of cylinder full of water 201051 gMass of unknown object 15211 gMass of unknown object cylinder and water (minus spill-over) 212219 gDensity of unknown object g

Show work for density calculation and use the correct No of significant figures

Liquid

Mass of empty cylinder _______g

Mass of cylinder and unknown liquid _______g

Mass of liquid _______g

Volume of unknown liquid measured 100 mL

Solid (regular shape)

Wooden cylinder mass ________g

Wooden cylinder height ________g

Wooden cylinder diameter ________g

Calculated cylinder volume ________cm3 (mL)

Solid (irregular shape)

Mass of object ________g

Original volume ________mL

Volume w object ________mL

Volume of object ________mL

Calculations

1 Calculate the density of the unknown liquid Show work

2 Calculate the density of the wooden cylinder Show work

3 Calculate the density of the irregular object Show work

Atomic StructureState goals 101 102 105 305

Lesson plan 1

Objective to trace the refinement of the modern atom through pictures

Clue InvestigationDivide the class into 7 groups Each group receives a face(Democritus Dalton Thomson Rutherford Bohr Millikan and Schrondinger)Go to httpdbhswvusdk12causGalleryGalleryMenuhtml to print the 7 faces of men to be distributed

Day 1 Clue The following men have something to do with matter its structure and properties Who are they What did they do Tell students to search their text other texts (college) the internet and an encyclopedia (no names are given)

Day 2 Clue These men developed our current atomic theory Who are they What did they do (No names are given)

At this time each group should make a report which leads to discussions and further teaching such as Daltonrsquos atomic theory Rutherfordrsquos gold foil experiment Millikanrsquos oil drop experiment etc Note Democritus (400 BC) is the most difficult person to find information about You may have to coach the group that receives his picture Also you may have to give the name of Millikan etc

Lesson plan 2Isotopes of ldquoMarbleliniumrdquo an imaginary element

Imaginary symbol Mb

Introduction In this investigation you will determine the relative abundance of the isotopes of marblelinium and the masses of each isotope You will then use this information to determine the average atomic mass of this imaginary element Recall the average atomic mass of an element is the weighted average of the masses of isotopes (weighted much like a test is weighted more than an individual homework grade) of the element The average is based on both the mass and the relative abundance of each isotope as it occurs in nature

Problem What are the masses and relative abundances of isotopes of marblelinium and what is the average atomic mass of the element

Materials laboratory balance centigram scale 20 marbles in a ldquoresealablerdquo bag

Procedure 1 Remove the 20 marbles from the ldquoresealablerdquo bag and record the mass of each marble

to nearest 001 g by placing each one individually in a polystyrene weighing dish on the balance pan

Data Table Combined mass (to the nearest 001 g) of the 20 marbles ________g

Mass Mass

6 16 7 17

Calculations 1 Inspect your data (mass) carefully Determine the number of isotopes Mb

that are present ________________

2 Calculate the fractional abundance of each isotope in your sample (the

number out of 20 that weigh close to each other)

3 Calculate the (relative) atomic mass of each isotope4 Using the fractional abundance from 2 and the (relative) atomic mass of each

isotope in 3 calculate the average atomic mass of Mb

Ave at mass = (rel at mass of an isotope) X (fractional abundance) + (rel at mass of an isotope) X (fractional abundance) + helliphelliphellip

Post-Lab

1 Was the mass of 20 marbles equal to 20 times the mass of one marble Explain

________________________________________________________________

2 An element consist of 9051 of an isotope with a mass of 19992 amu 027 of an isotope with a mass of 20944 amu and 922 of an isotope with the mass of 21990 amu Calculate the average atomic mass and identify the element

Lesson plan 3

Objective to determine electrons protons neutrons mass number and atomic number and to relate these numbers to symbols

element protons mass number electrons atomic number neutrons

Se _______ _______ _______ _______ 45

______ ______ 16 9 _______ ______

______ 14 28 ______ _______ ______

______ ______ 1 ______ _______ ______

isotope nuclear atomic masssymbol symbol number number protons neutrons

hydrogen-2 21H ______ ______ ______ ______

______ 8338Sr ______ ______ ______ ______

______ ______ 92 ______ ______ 146

______ C ______ ______ ______ 8

______ ______ ______ 201 80 ____________________________________________________________________________________symbol protons neutrons electrons net-charge

______ 33 42 ______ 3+

12852Te2-- ______ ______ 54 ______

______ 16 16 16 ______

______ 81 123 ______ 1+

19578Pt ______ ______ ______ ______

23892U ______ ______ ______ ______

______ 20 20 ______ 2+

______ 23 28 20 ______89

39Y ______ ______ ______ ______

_____ 35 44 36 ______

______ 15 16 ______ 3-

Arrangement of Electrons in AtomsState goal 301

Lesson plan 1

Investigation The Bohr Model of the Hydrogen Atom

Reference pages Chemistry Addison-Wesley p 361-362 372-375 379-380

Abstract After Rutherfordrsquos discover of the nucleus of an atom in the famous gold foil experiment Neils Bohr proposed in 1913 a newer model of the atom in which electrons are not randomly found in the electron cloud but found only in certain energy levels (shells or orbits) around the nucleus The energy levels were labeled ldquonrdquo where n = 1 2 3 4 etc He proposed that electrons had fixed energy when they remained in the energy level and the electrons do not lose energy and fall into the nucleus Scientists were puzzled why electrons didnrsquot lose energy and spiral into the positive charged nucleus Also the Bohr model proposed that energy levels (shells or orbits) were not equally spaced from the nucleus they become more closely spaced the farther away from the nucleus The model also describes how electrons can move from one level to another energy level electrons in an atom can transition from their ground state the lowest energy level they can occupy to an excited state a higher level by absorbing an appropriate amount of energy called the quantum This energy could be supplied by heat or electricity Absorbing energy less than the quantum no transition of the electron can occur Electrons could transition by absorbing energy moving from n = 2 to n = 4 (2 as ground state to the excited state 4) and transition back to n = 2 by giving off this energy in the form of light (radiant energy) hence emission spectrum line are formed Emission spectrum lines are unique to each element and these lines furnish scientist a way to distinguish one element from another The Bohr model was able to explain the visible spectrum lines of the hydrogen atom observed in his day by numerous investigators and explain any species that has a one electron system such as He+ Bohr was able to calculate the energy frequency and wavelength of light (radiant energy) given off during an electron transition to a lower state Its shortcoming which led to the modelrsquos downfall was that it could not explain the spectrum lines of many-electron atoms To calculate energy in joules (J) of a quantum of light given off E = hv

h is a constant known as Planckrsquos constant and has a value = 663 X 10-34 J-s

v is the frequency of light given off when a electron transitions back to a lower energy level it is a Greek small letter called ldquonurdquo pronounced ldquonewrdquo and has the unit 1s

To calculate frequency (v) or wavelength (nm) of light (radiant energy) given off v = cλ

c is the speed of light 300 X 108 ms

λ is the wavelength of that radiant energy (light) the units are usually in nm

Objectives 1You are to observe the emission spectrum lines of the hydrogen and helium atoms by using a spectroscope glass tubes containing the two gases at low pressures and a power source 2 You are to relate the visible emission spectrum lines seen to the electron transitions in hydrogen atom and to perform the appropriate calculations

Safety precaution The power source supplies a high voltage

The investigation1 Observed the emission spectrum lines of the hydrogen atom and the helium atom2 Which atom has more emission spectrum lines Why3 Draw the emission spectrum lines below as seen by you through the spectroscope of

hydrogen atom only Use colored pencils if possible4 In all three or four emission spectrum lines of hydrogen atom drawn indicate which

electron transition correspond to which lines Use the hand out reference sheet class overhead transparencies or text pages listed

5 Estimate the three or four wavelengths observed in the spectroscope for the hydrogen atom (nanometers -nm) List in the table below

6 Find the three or four correct wavelengths for these emission spectrum lines of the hydrogen atom on the hand out reference sheet class transparency or text pages listed List in the table below

H2 emission spectrum lines drawn here

TableQuestion 5 (above) answer Question 6 (above) answer

Estimated wavelengths observed (nm) Correct wavelengths (nm)

7 Order the three or four spectrum lines observed in the hydrogen atom only a) from lowest energy first to highest energy given off last b) from lowest frequency first to higher frequency given off last c) from shorter wavelength first to longer wavelength last Notice the less than signs

Energy lt lt lt lt Frequency lt lt lt lt

Wavelength lt lt lt lt

8 Bohr calculated the energy change by electron transitions by the following equation

∆E = 218 X 10-18 (1 n2final - 1 n2 initial ) Joules

where n is the energy level of the transitions If an electron fell from n = 3 to n = 2 then initial is 3 and final is 2

Calculate the energy change (∆E) frequency and wavelength in nm of light given off from n = 3 to n = 2 transition in the hydrogen atom Circle all three of your answers Donrsquot forget units Use the space below

Name_______________________________

Pre-lab The Emission Spectrum Lines of the Hydrogen Atom

1 In the Bohr model of the atom where are electrons found

2 The energy level is given what letter symbol

3 When an electron absorbs a certain amount of energy called the _________________

it can transition to a higher energy level

4 What is the main safety precaution in this investigation

5 What causes emission spectrum lines

6 Calculate the energy in joules of a quantum of violet light that has a frequency of 615 X 1014 1s

7 Use the frequency above and calculate the wavelength in nm of this violet light

Lesson plan 2

Objective to become familiar with quantum numbers and atomic orbitals

1 a What does the principal quantum number specify

b How is it symbolized

c What are shells

d How does n relate to the number of orbitals per main energy level

2 a What information is given by the angular momentum quantum number

b What are sublevels (subshells)

3 For each of the following values of n indicate the number of orbitals per main energy level and types of sublevels (subshells) possible for the main energy level given below See Table 4-2

4 a What information is given by the magnetic quantum number

b How many orbital orientations are possible in each of the spd and f sublevels

c Explain and illustrate the notation for distinguishing among the p orbitals in a subshell

5 a What is the relationship between n and total number of orbitals in a main energy lever

b How many total orbitals are contained in the 3rd main energy level And the 5th

6 a What information is given by the spin quantum number

b What are the possible values of this quantum number

7 How many electrons could be contained in the following main energy levels with n equal to

8 What is the maximum number of electrons in an atom that can have the following quantum numbersa n = 2 s = -12

b n = 5 1 = 3

c n = 4 1 = 3 m = -3

The Periodic Table and PeriodicityState goal 201

Lesson plan 1

Objective To discover the periodic trends of certain physical properties of elements related to their position on the Periodic Table of Elements

Background The Periodic Table is arranged according to the Periodic Law The Periodic Law states that when elements are arranged in order of increasing atomic number their physical and chemical properties show a periodic pattern Students can discover these patterns by examining the changes in properties of elements on the Periodic Table The properties that will be examined in this lesson are atomic radius first ionization energy and electronegativity (definitions)

TEACHER NOTE The teacher may encourage the students to take notes as they go through the questions (they may become difficult to recall while switching back and forth between pages) Students need to be familiar with the terms atomic radius ionization energy and elctronegativity

Lesson In this exercise you will look at a few physical properties of elements and how those properties are related to their position on the Periodic Table Analyze the data found on the Periodic Table sites to answer the questions listed below When performing your activities you may return to this page by clicking on the Go to Lesson link

Activities

1 Explore some on-line periodic tables Use the URL wwwchemicoolcom for the Cool Periodic Table

2 Use the Cool Periodic Table link For each of the first three elements in rows 2 and 3 (Li Be B then Na Mg Al) find the Atomic Radius (click on the element symbol)

o What appears to be the trend in atomic radius as you move from left to right in a row

o What appears to be the trend in atomic radius as you move down a column o Predict the change in atomic radius of the next elements in a row (C Si) then

check those properties Do they match your predictions o Check the atomic radius of the next elements in the series (N P) How do

they fit the predicted pattern o Is the pattern of atomic radius absolute or general (always true or generally

3 Repeat the same steps and questions but look at the property of first ionization energy and then repeat again for electronegativity

4 Consider all three of the properties that you have examined

o State the general trend for each property if you move from left to right on the Periodic Table Now state the general trend from top to bottom

o How do these properties show periodicity (periodic trends)

5 Use the links given below to examine the same three properties graphically

6 View the line graph of atomic radius

o What do the different colors show o Can you see a pattern in the second period that is repeated in the third period o How does this graph agree with your observations of atomic radius made earlier o Why do the fourth and fifth periods have more dots and different patterns

7 Find the same type of graph for 1st ionization energy (enthalpy) and electronegativity Answer the same questions for these graphs as you did for the atomic radii graph

8 Use the color-coded tables atomic radius 1st ionization energy and electronegativity to answer the questions below

o How does this show periodic trends of the selected property o Which method did you find most informative o Which method was easiest to see the general pattern and not get confused by

exceptions in the pattern

CreditsKelly Dobbins Marty Ponder Lisa Rice and Angie RobertsonIonic and Covalent Bonding

State goal 107

Lesson plan 1

Molecular ModelsConstruct molecular models of the following covalent compounds and fill in the following chart

Molecule Lewis Structure

No of LP No of SP around central atom

PolarNonpolar Molecule

Lesson plan 2

Objective To determine properties of ionic and covalent compounds

Name_______________________ Score__________________

1 Consider the following six compounds and answer the following questionsNaC1 CH4 (methane) NH3 (ammonia) MgF2 KF BH3 (boron trihydride)

(a) Classify the above six compounds as ionic or covalent (11)

(b) Research the boiling points and melting points of each Which compounds have the highest boiling and melting points Go to the media center public library or internet (httpchemfindercamsoftcom) (11)

(c) Which compounds occur in the solid liquid and gaseous state (11)

(d) Which are good conductors of electricity when in the liquid state or when dissolved in water Use a reference book or internet search engine (11)

2 Compare and contrast your finds from above (11)

3 Using the electron configuration explain how Mg would combine with F to form an ionic bond (11)

4 Fill in the following chart (34)

Compound Elements Electroneg Elect Diff Bond Type Charge

Lesson plan 3Objective To determine shape and polarity of molecules

Give the 1)Lewis Structure 2)Bond Angle 3)Shape 4)Molecular Polarity of each Molecule Do not give polarity of the ions

MolecularLewis Structure Bond Angle Shape Polarity

1 CO________________________________________________________________________

2 H2O2

________________________________________________________________________

3 CH3F

________________________________________________________________________

5 A1C13

________________________________________________________________________

6 C12CO

________________________________________________________________________

7 SO32-

________________________________________________________________________

8 SeC14

____________________________________________________________________________________________________________

9 C1F4+

_______________________________________________________________________

10 XeOF4

________________________________________________________________________

11 NO2

________________________________________________________________________

12 N2O

Lesson plan 4Objective To determine shape and polarity of moleculesGive the 1)Lewis Structure 2)shape and 3)polarity of the following

1 A1C13

2 BeH2

3 SnC15 -

4 C12CO

5 IF4-

6 SF5+

9 XeO2F2

10 HCN

Chemical Quantities Names Formulas

State goals 103 202

Lesson plan 1Water of crystallization the hydrate

Objective- In this investigation you are to name several hydrates and to heat hydrates which drives off their water of crystallization

Introduction- Ionic compounds often crystallize from solution with molecules incorporated within the crystal structure of the solid Such compounds are referred to as hydrates This water of crystallization may be driven off by the application of heat to form an anhydrous (without water) compound

In writing the formula of a hydrate a dot is used to connect the formula of the compound and the number of water molecules per formula unit Crystals of copper(II) sulfate pentahydrate (CuSO45H2O) always contain five molecules of water for each copper and sulfate ion pair The deep-blue crystals are dry to the touch When heated over 100C the crystals lose their water of hydration (water of crystallization)

CuSO45H2O(s) == CuSO4(s) + 5H2O(g) (blue crystals) (white anhydrous solid)

Hydrates are named by group prefixes (mono-di- tri- tetra- penta- hexa- hepta- octa- nona- deca-) For example BaCl22H2O is named barium chloride dihydrate

Procedure1 Place about 05 g of CuSO45H2O in a clean small evaporating dish2 Set up a wire gauze on a metal ring and prepare to heat the sample in the burner flame

Begin the heating with a very small flame If there is any evidence that the material is a bout to spatter remove the heat immediately Record any changes in appearancecolor as the hydrate is heated

3 When it is apparent that most of the water has been driven from the sample increase the size of the flame Stir the salt with a clean stirring rod until the sample is uniform in texture and appearance

4 Remove the heat and allow the dish to cool completely to room temperature5 When the anhydrous metal salt has cooled to room temperature add water dropwise

Record any changes in appearancecolor 6 Clean out the evaporating dish repeat the procedure with the other available metal

hydrates NiCl26H2O CoCl26H2O CrCl36H2O BaCl22H2O7 As a more vivid demonstration of the ability of anhydrous salts to absorb moisture do the

following Weigh an empty clean watch glass (to the nearest 001 g) then add about a teaspoon of anhydrous calcium chloride to the watch glass and reweigh Examine the salt from time to time during the remainder of the lab period and reweigh the watch glass and contents before leaving lab Calcium chloride is an excellent desiccant and is able to absorb so much moisture from the air that it usually forms a solution itself A salt that

absorbs such a great deal of water to form a solution is said to be deliquescent Calculate the mass of water absorbed by the anhydrous calcium chloride Calculate what percentage of its own weight the CaCl2 sample was able to absorb in moisture during the lab period

Data Sheet1 Copper (II) sulfate pentahydrate

Observation before heating _______________________________________________________________________________________________________________________________________________________________________________________________________________Observation after heating_______________________________________________________________________________________________________________________________________________________________________________________________________________Observation on adding water______________________________________________________________________________________________________________________________________________________________________________________________________________

2 Nickel (II) chloride hexahydrate

3 Cobalt(II) chloride hexahydrate

Observation before heating _______________________________________________________________________________________________________________________________________________________________________________________________________________Observation after heating

______________________________________________________________________________________________________________________________________________________________________________________________________Observation on adding water______________________________________________________________________________________________________________________________________________________________________________________________________________

4 Chromium (III) chloride hexahydrate

5 Barium chloride dihydrate

Calcium chloride (anhydrous)

Observation on absorbing moisture from air ________________________________________________________________________________________________________________________________________________Mass of empty watch glass g _______________________________________________Mass of watch glass plus anhydrous CaCl2 _____________________________________Mass of watch glass plus CaCl2 on standing g __________________________________

Mass of water absorbed g __________________________________________________Percent water absorbed ____________________________________________________

Pre-Lab

Name the following hydrates

1 Ce2(CO3)35H2O

2 BeCl22H2O

3 Na2CrO410H2O

4 LaCl37H2O (Lanthanum is always 3+ hence no roman numeral is used to name)

5 LiNO2H2O

6 Mg(BrO3)26H2O

7 Fe(NO3)39H2O

8 IrBr34H2O

9 Co3(PO4)28H2O

10 CrPO43H2O

Look up the words deliquescent hygroscopic efflorescent and distinguish among all three

Chemical ReactionsState goal 203 205

Lesson plan 1Beginning Balancing Chemical Equations

IntroductionThis assignment is a useful tool for CP students and Honors who need a beginning

understanding of the Law of Conservation of Atoms and who have trouble ldquoseeing moleculescompounds in their headrdquo as balanced This assignment makes use of the online game Chembalancer After successful completion of this web game a chemistry student should be able to master the balancing of these chemical equations The assignment could be done in computer lab or done as a homework assignment

Directions 1 Go to httpwwwdunorgsulanchembalancer and check it out

2 Go to httpwwwdunorgsulanchembalancerworksheethtm Print out a copy to turn in you answers if requested by your teacher The teacher may only want for you to show your finalhtm page

3 Students are to do 12 and 13 also which only appear on the worksheet

4 To reinforce your knowledge of balancing answer the following questions after successful completion of the game

a How many atoms of each element do you find in the following formulas

1 Ca3(PO4)2 2 3Mg(C2H3O2)2

b Study the following balanced equation and answer the following questions

2H3PO4 + 3Ca(OH)2 Ca3(PO4)2 + 6HOH

1 How many phosphate anions are on a side

2 How many hydroxide anions are on a side

3 What is the total number of oxygen atoms on a side

Lesson plan 2

Objective To write 5 types of balanced chemical equations while observing and participating in the reactionsApparatusmaterialequipment needed

1 Hoffman apparatus 6M H2SO4 direct power source2 KClO3 MnO2 4-5 gas collecting bottles trough large mouth test tube and one-hole

stopper with L-glass bend for stopper and enough tubing to reach bottles3 Mg ribbon S deflagrating spoon steel wool as a source of iron litmus paper4 Cu and 1M AgNO3 Al and a saturated solution of CuCl2

5 Solutions of BaNO3 and H2SO4 solutions of Pb(NO3)2 and KI6 Natural gas outlet rubber tubing connected to funnel to dip into a beaker of liquid

bubbles for making methane filed bubbles for explosion7 Solid Ba(OH)2 and solid NH4SCN8 A prompt of the 5 types of reactions on the board that represent the demonstration

reactions

WRITING AND BALANCING CHEMICAL EQUATIONS- AN INTERACTIVE DEMONSTRATION

1 The electrolysis of watera How many mL of oxygen gas are produced in one arm of the Hoffman apparatus

b How many mL of hydrogen gas are produced in the other arm

c Write and balance the equation for the electrolysis (decomposition) of water What is the catalyst for this reaction Where is the catalyst placed in the equation

d How does the experimental volume ratio compare to the coefficient in a balanced equation

e Look at the power source and determine the anode (+ terminal) and cathode (- terminal) If one could not determine the ratio of the two gases how could one distinguish in which arm the gases are found

f When both gases are tested with a burning splint which gas is explosive

2 The decomposition of potassium chlorate with heat and MnO2 as a catalyst

a Write and balance the decomposition reaction Place the catalyst appropriately in the equation See the prompt on the poster board

b If all the oxygen is produced in this reaction what solid remains in the test tube originally containing potassium chlorate

3 The synthesis of compounds in the oxygen producedWrite and balance the following synthesis reactionsa Hot solid magnesium placed in the oxygen gas forms what ionic compound

b Hot solid iron placed in the oxygen gas produces an unusual iron solid Fe304

c Hot molten sulfur placed in the oxygen gas forms a gaseous molecular compound sulfur dioxide

d The sulfur dioxide gas will dissolve in water to form sulfurous acid (H2SO3)

4 Write and balance the following single replacement reactions andor answer the following questions about single replacement

a Copper metal is placed into an aqueous solution of silver nitrate

b A metal (cation) replaces what in the single replacement reaction

c A nonmetal (an anion) replaces what in a single replacement reaction

d Aluminum foil rolled up into a ball is added to aqueous copper (II) chloride

e Which element becomes free (uncombined)

5 Write and balance the following double replacement reactions andor answer the following questions a Which ion in a compound is written first the cation or anion

b After ions are exchanged what must be checked before balancing c Aqueous barium nitrate is added to aqueous sulfuric acid (H2SO4)

d Solid lead (II) nitrate is mixed with solid potassium iodide

e Is the yellow compound the only product of this reaction

f What happened before the reaction was mixed What does this tell us about the solid reaction

6 The complete combustion of natural gas mainly methane CH4 a The complete combustion you observe is the chemical reaction between what two

reactants

b What products are produced

c Is the combustion of the hydrocarbon fuel endothermic or exothermic

d Write and balance the complete combustion of methane

7 As seen above reactions can give off heat Reactions can also take in heat a When solid barium hydroxide octahydrate is mixed with ammonium thiocyanate a double replacement reaction takes place Put your hand on the beaker which contains the reaction How does it feel

b Has the reaction gained heat or lost heat What is the term for a reaction that describes your answer

c Do reactants or products have more heat content

d Do research on manually activated cold packs used in sports medicine

Lesson plan 3Equation Writing Activity

A Write and balance each equation in which a reaction occurs Some double and single replacement reactions do not occurYou will have to

1) Check the Activity Series for single replacement reactions on the State Chemistry Reference Tables 2) check Solubility Rules for double replacement reactions on the State Reference Tables and 3) circle each product in each double reaction that makes it occur

1 Zinc + hydrochloric acid

2 Sodium chloride + sulfuric acid

3 Sodium chloride + silver nitrate

4 Sodium hydroxide + hydrochloric acid

5 Potassium hydroxide + sulfuric acid

6 Potassium chlorate (heated)

7 Iron (II) sulfide + hydrochloric acid

8 Copper (II) sulfate + hydrogen sulfide

9 Silver nitrate + hydrogen sulfide

10 Sodium nitrate + sulfuric acid

11 Silver nitrate + copper (assume Cu2+ )

12 Aluminum sulfate + ammonium hydroxide

13 Potassium chloride + sodium nitrate

14 Iron (assume Fe3+ ) + sulfur

15 Magnesium + oxygen

16 Electrolysis of water

17 The complete combustion of butane C4H10

18 Calcium + oxygen -gt

19 Copper (II) sulfate + iron (assume Fe2+ )

20 Sulfuric acid + iron (assume Fe3+ )

21 Sulfuric acid + barium chloride

22 Sulfuric acid + sodium hydroxide

23 Copper (II) sulfate + zinc

24 Copper (II) chloride + silver

25 Aluminum + oxygen

26 Silver + oxygen

B Indicate the type of reaction represented by equations 1-20 (even if a reaction does not take place) Use the terms synthesis decomposition single replacement double replacement and combustion

1 112 123 134 145 156 167 178 189 1910 20

Lesson plan 4

Chemical Equations Objective Students will model the process of reactants changing into products during a chemical reaction Materials

12 gumdrops jelly beans or suitable alternative each of three different colors Small toothpicks

Procedure

1 Designate each color of gumdrop to represent a single atom of an element2 Make three molecules each of hydrogen (H2) and oxygen (O2) Model a reaction

between the one molecule of H2 with one molecule of O2 by splitting the molecules (joined by the toothpicks) and joining one oxygen atom with two hydrogen atoms The other unreacted oxygen atom must react with another hydrogen molecule to form a second water molecule All of the atoms of reactants must combine to form molecules of product

3 Write a balanced equation for the formation of water H2 + O2 reg H2O 4 Repeat step 2 for the reaction of methane with oxygen You will have three molecules

of methane and three of oxygen5 Write a balanced equation for the formation of carbon dioxide and water from

methane and oxygen The reactants are CH4 and O2 and the products are CO2 and H2O Remember to make sure the equation is balanced

Follow-up questions1 The space shuttle uses hydrogen and oxygen as fuel for lift-off After it is burned what

happens to it What is the large white plume of ldquosmokerdquo that you see at the time of lift-off2 Your car engine uses a hydro-carbon as fuel Methane is also a hydro-carbon Knowing this

what do you think the main by-products of your carrsquos engine are In other words what are the main products of the reaction of octane and oxygen

3 Why is it necessary to balance a chemical reaction Hint If you are in a lab and you only want a certain amount of product what would you want to ensure before you start

2 Types of Solution Reactions (Precipitation Acid-base) and Oxidation-ReductionState goal 2024 203 206

Lesson plan 1

Objective 1)To track the transfer of electrons in an oxidationreduction reaction and to assign oxidation numbers 2) To identify oxidizing and reducing agents and to assess practical examples of redox reactions

1 Assign oxidation numbers to the following a Cl2 b HCl c Ca(ClO3)2 d Na2O

e KMnO4 f K2Cr2O7 g C6H12O6 h PO43-

i Cu(NO3)2 j SO3

2 Circle the oxidized element and ldquoX-outrdquo the reduced element List the oxidizing agent and reducing agent in the following equations

a H2S + HNO3 ----gt H2SO4 + NO2 + H2O

b Zn + HCl ----gt ZnCl2 + H2

What is the oxidation half-reaction and the reduction half-reaction of equation b

c C4H10 + O2 ----gt CO2 + H2O

d P + HNO3 + H2O ---gt NO + H3PO4

What is the oxidation half-reaction and reduction half-reaction ofequation c

3 What is oxidation What is reduction Define oxidizing agent and reducing agent

4 What are three practical applications or familiar occurrences of redox reactions Modern p 590-616 or see the experiment on oxidation-reduction

Lesson plan 2Copper Plating Making Ornaments

This lab can be used the last day of class before Christmas break It is a review of electrochemistry and ldquogetsldquo the attention of students

Objective Students are to make holiday ornaments by plating copper out on another metal by an oxidation-reduction reaction

Materials

Galvanized sheet metal cut into 5 X 5 cm squares with a hole drilled in one of the cornersMasking tapePencilUtility knifeSteel woolCotton balls01 M copper (II) nitrate 25 mL per student

Procedure

1 Polish both sides of the metal with steel wool2 Cover the entire metal with masking tape3 Draw a diagram with a pencil in the holiday spirit on both sides of the tape example of drawing snowflake4 Cut out the design with the utility knife Be careful 5 Dip the exposed metal into the 01 M copper (II) nitrate solution andor dap on the solution with cotton balls using tongs Do not touch with fingers6 Rinse ornament carefully in water and allow to dry7 Remove excess tape8 A Write the molecular equation for the reaction B Write the two half-reactions C What metal underwent reduction oxidation9 Hang your ornament on your tree each year to remind you of your chemistry experience

______________________________________________________________________________

Lesson plan 3

Citrus Batteries Objective Students will make a model of a voltaic cell with the use of a lemon Materials

Lemon Zinc Sheet cut into 5 inch x 125 inch strips Copper Sheet cut into 5 inch x 125 inch strips Voltmeter Fine grade sandpaper

Procedure

1 With sandpaper polish the zinc and copper strips2 Push the copper strip into the lemon Leave about three-quarters of an inch of the

strip sticking out3 Do the same with the zinc strip as you did with the copper Make sure the copper and

zinc strips are separated by about a half an inch 4 Touch both leads at the same time with your tongue Record your observations5 With the voltmeter determine what voltage you are able to produce

Follow-up questions1 Explain the sensation that you felt on your tongue2 Which of the two metals is the anode Which is the cathode How do you know3 Write an equation describing the flow of electrons through the lemon and leads

Lesson plan 4

Ions in Solution Objective Students will demonstrate that solutions containing ions conduct an electric current Materials

Table salt (NaCl) Baking Soda (NaHCO3) Vinegar (acetic acid in solution) Sugar (Sucrose) Distilled water 2 foot long pieces of bell wire with the ends scraped bare clear plastic cup 3 - 15 volt batteries masking tape

Procedure

1 Connect the batteries together end to end Make sure that the positive terminal on one touches the negative terminal on the other and then tape them together with the masking tape

2 Tape the exposed end of one piece of wire to the negative terminal in battery ldquocomplexrdquo and the other wire to the positive end

3 Fill your cup halfway with distilled water and hold the bare ends of the wires close together in the water Notice any sign of bubbles which would demonstrate that the liquid conducts electricity

4 Repeat step 3 with a concentrated solution of sugar acetic acid concentrated solution of sodium chloride (table salt) tap water and a concentrated solution of baking soda (sodium bicarbonate)

Follow-up questions1 Document which solutions conduct electricity better and compare the reasons for each2 Were there any samples that did not produce electricity Which ones and why didnrsquot they3 Would the amount of batteries used really make a difference to the data Why or why not

Lesson plan 5

Mixtures as Solutions or Colloids and the Tyndall Effect Objective Students will classify mixtures as solution or colloids by virtue of the Tyndall Effect Materials

Cup Black Construction Paper Masking Tape Teaspoon Flashlight 3 Rectangular Jars (Rectangular mason jars work well) Distilled water Cornstarch Sodium Bicarbonate (NaHCO3)

Procedure

1 With the construction paper make a cone and tape to fit over the lens of the flashlight

2 Make a paste by mixing a quarter teaspoon of cornstarch with 4 teaspoons of water in a cup

3 In Jar 1 fill with distilled water In Jar 2 add a quarter teaspoon sodium hydrogen carbonate and fill and mix with water In Jar 3 add the cornstarch paste and fill and mix with water

4 Turn out the lights in the room Shine your flash light at each of the jars and document your observations

5 Clean the jars when finished and remove the construction paper from the flashlight

Follow-up questions1 Was the light beam visible in any of the jars Which one(s) Why not in all2 Predict what you would observe if you were to replace the sodium hydrogen carbonate with

sugar or table salt3 What is the particle size difference of the solute which make up a colloid and a solution

______________________________________________________________________________

StoichiometryState goals 202 204 302

Lesson plan 1

Objective to calculate beginning stoichiometric relationships- mole-mole mass-mole and mole-mass

1 To make oxygen in the laboratory potassium chlorate is decomposed as follows

2KClO3(s) ----gt 2KCl(s) + 3O2(g)

a How many moles of O2 form when 37 moles of KClO3 decomposes

b If 75 moles of KCl are formed how many moles of O2 are formed

c If 300 moles of KClO3 are decomposed how many moles of each product are formed

2 Consider the balanced equation

2CaCO3(s) + 2SO2(g) + O2(g) ----gt 2CaSO4(s) + 2CO2(g) a If 250 moles of each product are formed how many moles of the gas SO2 reacted b How many moles of the gas O2 reacted c How many grams of O2 reacted

d In the above equation 272 grams of the solid CaSO4 were produced how many moles of CaCO3 reacted

3 a In the formation of aluminum sulfide as seen below how many moles of aluminum are

required to react completely with 186 moles of sulfur

16Al(s) + 3S8(s) ----gt 8Al2S3(s)

b How many moles of aluminum sulfide can be formed

c How many grams of aluminum sulfide can be formed

4 a When 500 grams of silicon dioxide is heated with excess carbon as seen below how many moles of each product can be formed

SiO2(s) + 3C(s) ----gt SiC(s) + 2CO(g)

c How many grams of each product can be formed

______________________________________________________________________________

Lesson plan 2

Pre-laboratory Yield of a Compound

Name__________________________________

1 What is stoichiometry

3 What acid is used in this experiment What terms are used to describe this acid

4 Why does one slowly add 30 M hydrochloric acid to the sodium hydrogen carbonate

5 What is the formula for finding percent yield

6 Define actual yield and theoretical yield

7 Carbonic acid is a by-product in this experiment It immediately decomposes to what two products

Yield of Compound

Objective In this experiment you will measure the mass of the solid product NaCl produced which is the actual yield of your experiment Secondly you will calculate the theoretical yield of the product NaCl from the stoichiometry of the balanced chemical equation Then you will calculate your percent yield of the NaCl from the following equation

yield = (actual theoretical) X 100

Actual yield-the amount of product formed when the reaction is carried out in the laboratoryTheoretical yield-the amount of product formed according to the stoichiometry calculation

Apparatus

balance centigram spatula electric heater evaporating disheye dropper

Chemicals

sodium hydrogen carbonate30 M hydrochloric acid

Safety Take the necessary safety precautions Wear safety goggles and apron HCl is caustic and corrosive Avoid breathing vapors If any acid should spill on you wash the area with water or if the acid spills on the table use acid neutralizer and then wipe up

Procedure

1 Obtain an evaporating dish Measure the mass of a clean dry evaporating dish to the nearest centigram Record this mass in the data table

2 Add between 200-275 g of sodium hydrogen carbonate to the evaporating dish Measure the mass of the sodium hydrogen evaporating dish Record this mass in the data table

3 Slowly add about 10 mL of the 30 M hydrochloric acid to the sodium hydrogen carbonate in the evaporating dish Do not let any solid product bubble out with the gas Then carefully add the 30 M hydrochloric acid with a medicine dropper drop by drop until the bubbling stops

Note The solid sodium hydrogen carbonate remains in the bottom of the evaporating dish unreated and therefore you must gently swirl the

evaporating dish between drops to ensure all the solid reacts

4 Place the evaporating dish on an electric heater select a moderate heat You may have to adjust the heat knob as needed

5 Gently boil the water from the evaporating dish until only a dry solid remains Begin to heat slowly when almost all the water is evaporated Do not let any of the solid product escape

6 Turn off the heater Place the evaporating dish with your product in an oven set at 200OC over night

7 Determine the mass of the cooled dish and solid product Record this mass in the data table

7 Calculate the theoretical yield of the NaCl you produced from the balanced chemical equation Do this calculation under Calculations (7)on accompanying Data Sheet

8 Dispose of your solid product in the drain Clean all laboratory apparatus Wash your hands and finish your calculations

Lesson plan 3

The Limiting Reactant

Objective To calculate the theoretical yield to identify the limiting reactant to calculate the excessive reactant remaining in a stoichiometry problem

1 How many grams of magnesium oxide can be produced by reacting 200 g of magnesium with 160 g of oxygen

2 Sulfuric acid react with aluminum hydroxide by double replacement If 300 g of sulfuric acid reacts with 250 g of aluminum hydroxide identify the limiting reactant

b Determine the mass of excessive reactant remaining

c Determine the mass of each product formed

3 A student reacts 595 g of butane (C4H10) with 165 g of oxygen in a complete combustion reaction What is the limiting reactant Which reactant is in excess What is the theoretical yield of carbon dioxide

Lesson plan 4

Stoichiometry Theoretical Mass vs Experimental Mass Objective Students will be able to cause a double replacement reaction between zinc acetate and sodium phosphate tri-basic Materials

Distilled water 100 ml graduated cylinder filter paper 4 grams of sodium phosphate tri-basic 3 grams of zinc acetate 150 ml beaker 250 ml beaker 400 ml beaker stirring rod ringstand funnel weighing dish electronic balances

Data Tables

Day Trial 1 Trial 2Mass of beaker 1

Mass of beaker + contents

Mass of filter paper (before experiment)

Mass of weighing dish

Mass of filter paper + weighing

dish (dry)

Trial 1 Trial 2

Mass of zinc acetate Mass of zinc phosphate

(experimental)

Average mass of zinc phosphate Theoretical mass of zinc

phosphate

Percent error

Procedure

1 Use the data chart to record the information2 Students should be wearing chemical splash goggles lab aprons and gloves3 Make sure to weigh the filter paper the weighing dish the beaker and the beaker

plus contents before starting the experiment4 Have students prepare solutions for the zinc acetate (solubility 1 grams per 23

milliliters of water) and the sodium phosphate tri-basic (solubility 33 grams per 100 ml of water at 25 degrees Celsius)

5 The two solutions should now be mixed together with a little agitation6 A precipitation of zinc phosphate will result The solution should now be filtered to

collect the precipitate7 A ring stand with a funnel in the ring with a hose from the funnel into the sink or a

beaker placed beneath the funnel should be fine for filtering8 Make sure the filter paper is placed properly in the funnel9 Pour the solution through the funnel being careful not to spill any over the sides10 Allow the precipitate to dry on the filter paper overnight or you may use a vacuum

filtration system to dry it out faster11 Weigh the filter paper with the precipitate in the weighing dish12 Record your results13 Repeat the experiment in a second trial to confirm your results

Follow-up questions1 Figure out what the theoretical mass of zinc phosphate should be based on the actual mass of

zinc acetate2 Show the calculations of the percent error of your experimental values vs theoretical3 Explain what factors may have contributed to the differences between the experimental mass

and the theoretical mass of the product4 Write an equation explaining the double replacement reaction

States of MatterState goals 302 401

Lesson plan 1

The Process of Sublimation and Deposition Objective Students will establish an apparatus that will demonstrate the process of sublimation and deposition Materials

Ice 3-4 strips of heavy thick cardboard Hot water (from a faucet) Two 8-oz clear plastic cups Small shallow container Small chunks of solid air freshener

Procedure

1 Drop some small chunks of air freshener in a cup2 Bend the cardboard in half along the width and lay them on the rim of the cup with

the air freshener in it3 Insert the second cup inside the first Please make sure that the second cup doesnrsquot

rest on the air freshener You may adjust the cardboard if necessary4 Fill the top cup with ice Be sure not to let any ice or water into the bottom cup5 Fill the shallow container about a third of the way full of hot water from the tap6 Gently place the cups in the shallow container in the hot water7 Notice what happens to the air freshener8 Now quickly remove the top cup from the bottom cup and look at the bottom

Follow-up questions1 What caused the sublimation of the air freshener2 What caused the deposition of the air freshener to the bottom of the top cup3 Is it possible to separate substances in some mixtures by sublimation

Gas LawsState goal 106Lesson plan 1

Objective to recognize the formula for and calculate various gas laws Directions In each problem list the law then solve

1 Some oxygen in a closed container occupies 250 mL when its pressure is 720 mm How many milliliters will it occupy when its pressure is 750 mm at constant temperature (240 mL)

2 A sample of contained gas occupies 500 mL at 270 degC What will be the volume of the gas in milliliters at standard temperature if the pressure remains constant (455 mL)

3 The pressure of a gas in a closed container is 300 kPa at 300 ordmC What will the pressure be if the temperature is lowered to -172 degC (The volume is constant in a closed container) (100 kPa)

4 A contained gas has a volume of 2400 mL at 700 torr pressure What pressure is needed to reduce the volume to 600 mL if the temperature remains constant (280 X 103 torr)

5 A gas has a volume of 2280 mL measured at 300 degC and 8080 mm of mercury in a closed container What volume of gas would be measured at STP (2184 mL)

6 A rigid steel cylinder has 2000 L of oxygen gas at a pressure of 2500 X 103 kPa and at 320 degC How many moles of oxygen does the cylinder contain How many grams of oxygen gas are contained (1972 mol 6309 g)

7 Calculate the relative rates of effusion of CH4 methane gas to helium gas at STP (He is 2 times the rate of methane)

Lesson plan 2

ldquoFlick your Bicrdquo The Determination of the Molar Mass of Butane

Objective Using the ideal gas law (equation) PV = nRT can be a good method for determining the molar mass of a gas in the laboratory The gas in the lighter is butane a hydrocarbon In this experiment we will use 008206 L-atm mol-K as R

Procedure 1 Remove the striking mechanism (flint wheel and spring) from the pocket lighter (BIC or Scripto) Pointed scissors are a useful tool for removing Remove warning label and all glue Measure the mass of the lighter on the balance to the nearest 001 g

2 Fill a 250 mL graduate cylinder completely full of water invert carefully and place it inside a pneumatic trough filled partially with water Be careful not to allow any air bubbles in the cylinder

3 Measure the temperature of the water ( It will be assumed that the gas will be at the same temperature) Obtain the barometer reading Use a water-vapor pressure table and Daltonrsquos Law to correct the correct pressure of the gas

4 Hold the lighter under the water and below the mouth of the inverted cylinder and press the ldquorelease areardquo on the lighter Make sure all the bubbles of the gas are going into the cylinder Collect between 230 to 250 mL of gas in the 250 mL graduate cylinder

5 Adjust the position of the cylinder in the water so that the water levels inside and outside the cylinder are the same Why You may have to add more water to the trough or more gas to the cylinder to achieve this to achieve this

6 Shake excess water from the lighter Blot dry with a paper towel and then use a cool setting of a hair dryer to blow off any droplets that remain Then measure the mass of the lighter again to the nearest 001 gWater-Vapor Pressure Table Temp ( C) Water-Vapor Pressure (atm) 18 0020 19 0023

20 0024 21 0025 22 0027 23 0029 24 0030 25 0031 26 0033 27 0035 28 0037

ldquoFlick your BICrdquoPre-Lab 1 Identify each variable and its unit that you will use in the ideal gas equation and identify the value of the constant R and its units

2 In this laboratory we will find the barometric pressure reading in our area by using wwwweathercom A student must look for this reading inserting our zip code and report it to the class The pressure reading must be determined at the time of the experiment Change this reading from inches of Hg to atm 2992 in of Hg = 1000 atm

Your pressure reading in atm is ___________________ 3 Observing the ldquoBICrdquo lighter how do you explain that you are determining the molar mass of a gas but butane is a liquid in the lighter

4 To calculate the molar mass you have to calculate the number of moles n of the gas present in the graduate cylinder by using the ideal gas law Then knowing the mass of the gas by measuring it on a balance you divide the grams of gas by the mole of the gas Molar mass is gmole Sample problem 240 mL of propane gas is collected over water by inverting a graduate cylinder full of water in a pneumatic trough filled nearly full of water The corrected pressure is 0998 atm and the measured temperature of water is 21 OC The mass of the gas collected was determined to be 042 g Calculate the molar mass of propane

5 In this experiment a gas is collected over water Not only is butane gas collected in the cylinder but some water vapor automatically is there causing the pressure of the butane gas in the cylinder not to be equal to the barometric pressure A correction must be made using a water-vapor pressure table and Daltonrsquos Law ( Pbar = Pgas + Pwater) If the barometric pressure is 0999 atm and the water temperature is 23C calculate the pressure for the butane gas in the cylinder needed for your ideal gas law calculationData

Barometer reading __________ atm

Pressure of butane (from Daltonrsquos Law and water-vapor table) __________ atm

Water temperature (gas temperature) __________ K

Volume of butane collected __________ L

Mass lighter before gas used __________ g

Mass of lighter after gas used __________ g

Mass of gas in graduate cylinder __________ g(mass of gas used)

Calculate the molar mass of butane using the ideal gas equation Show all work

Extension The percentage composition of the gas in the lighter was found to be as follows carbon 8263 and hydrogen 1737 Calculate the empirical formula of butane Use the empirical formula mass (efm) and your molar mass (MM) to determine the molecular formula of butane (n = MMefm) The butane gas may be impure and errors may occur in your experiment Round off ldquonrdquo to obtain a whole number to calculate molecular formula

______________________________________________________________________________

ThermochemistryState goals 302 303 304

Lesson plan 1Thermochemistry and Spontaneity

Introduction Thermochemistry is the relationship between chemical reactions and heat energy

Reactions can be exothermic (heat loss by a reaction) or endothermic (heat gain) but the natural tendency or driving force is for them to be exothermic

When a chemical reaction is exothermic the reaction can be spontaneous (will take place as written unless there is an outside source of energy) or nonspontaneous Clearly there must be anotherother driving forces of a chemical reaction other than just heat loss that makes a reaction spontaneous

Spontaneity of a reaction depends on two driving forces 1) change in enthalpy (exothermic or endothermic) and 2) change in entropy Entropy is a measure of disorder The natural tendency is for reactions to become more disordered

Demonstration and Discussion The teacher will dissolve 01 mole of each NH4NO3 MgSO4 and LiC2H3O2 in three

different test tubes which each contain 10 mL of distilled water A student assistant will be asked to record the temperature change as each substance dissolves The assistant may have to shake gently or stir the solution while recording and observing

The temperature changes of the three reactions or lack thereof allow for a ldquogoodrdquo discussion of change in enthalpy (exothermic endothermic) and heats of solution formation Equations for the dissolving substances are written on the board

Experiment In this experiment you will predict the spontaneity of the five reactions represented below Then in the laboratory you will attempt to carry out these same reactions to see if indeed your predictions are true Predict spontaneous or nonspontaneous

1 Fe(s) + 2HCl(aq) FeCl2(aq) + H2(g) _______________

2 Cu(s) + 2HCl(aq) CuCl2(aq) + H2(g) _______________

3 Ca(NO3)2(aq) + K2SO4(aq) 2KNO3(aq) + CaSO4(s) _______________

4 2NaCl(aq) + K2SO4(aq) 2KCl(aq) + Na2SO4(s) _______________

5 Ca(s) + 2HOH(l) Ca(OH)2(aq) + H2(g) _______________

Laboratory1 Place the following amounts in each of 5 small test tubes

Test tube 1 010 g of powdered iron

Test tube 2 3 pieces of copper shot

Test tube 3 1 mL of 050 M Ca(NO3)2

Test tube 4 1 mL of 050 M NaCl

Test tube 5 1 small piece of calcium metal

2 Add 1 mL 10 M HCl to each of the first two test tubes observing for a period of 5 minutes

3 Then add 1 mL of 050 M K2SO4 to test tube 3 and test tube 4 again observing for 5 minutes

4 Lastly add 2mL of distilled water to test tube 5 and observe for 5 minutes

ResultsReport on the spontaneity of each reaction you carried out Can you say definitely that for

those reactions that seemed to be nonspontaneous that they will never happen

Extension

If a reaction which is carried out at 250 ordmC losses 25 kJ of heat and gains 105 JK of entropy what is the numerical value of ∆G Is the reaction spontaneous or nonspontaneous

Lesson plan 2

Heats (Q) Lost or Gained by H2O

Objective To determine the amount of heat lost or gained during the heating curve of water

1 How much heat is absorbed when 350 g H2O(l) at 100OC is converted to steam at 100OC at standard pressure (1013 kPa or 100 atm)

2 How many grams of ice at 0OC and standard pressure (1013 kPa or 100 atm) could be melted by the addition of 375 kJ of heat

3 Calculate the following heat gained or lost at standard pressure in the following conditionsa 350 mol of water freezes at 0OC

b 044 mol steam condenses at 100OC

c 445 g of ice melts at 0OC

4 Calculate the heat gained by 100 g of ice when its temperature is raised from -200OC to -50OC

5 Calculate the heat gained by 250 g of water when its temperature is raised from 100OC to 900OC

Lesson plan 3

Heat of Fusion of Ice Objective Students will be able to estimate the heat of fusion of ice Materials

Ice 100 mL Graduated cylinder Thermometer Plastic foam cup Hot water

Procedure

1 Fill the cylinder with hot water from the faucet 2 Allow the cylinder to stand for 1 minute Pour the water in the sink3 Use the graduated cylinder to measure 70 mL of hot water 4 Pour it in to the plastic cup Record the temperature of the water5 Add a small cube of ice to the water and gently swirl the cup6 Measure the temperature of the water immediately after the ice cube has completely

melted7 Pour the water from the cup into the graduated cylinder and measure the volume8 Determine the heat of fusion of ice (kJmol) by dividing the heat given up by the

water by the moles of ice melted (Determine the mass of ice melted by subtracting the difference between the volume before the ice was added and the volume after it has melted)

Follow-up questions1 The heat of fusion of ice is 6 kJmol Why do you think there was a difference if any2 Calculate your percent error Use State Exam Reference Tables for formula3 How could you make this activity more error proof (Hint add detail)

______________________________________________________________________________

Reaction RatesState goals 305 403

Lesson plan 1

Temperatures and Reaction Rates Objective Students will observe the effect of temperature on the rates of chemical reactions Materials

4 plastic cups 4 Alka Seltzer tablets stop watch (es) thermometer ice graph paper hotcold water masking tape pen or pencil

Procedure

1 Mark the numbers 1 2 3 and 4 on four separate pieces of masking tape Label each of the plastic cups with one of the numbers

2 Arrange the plastic cups in numerical order and fill each about frac34 of the way full as follows (cup 1) cold water from tap with some ice (cup 2) cold tap water (cup 3) a mix of half cold and hot tap water (cup 4) hot tap water

3 Record the water of each cup with the thermometer4 Drop an Alka Seltzer tablet into each cup and time each reaction5 Record the time it takes for the reaction in each cup to complete6 Represent your data with a line or bar graph of temperature vs reaction time

Follow-up questions1 What relationship if any did you notice between temperature and reaction time2 What other ways could you test this relationship3 List several other factors that affect reaction rate and explain each

______________________________________________________________________________

Lesson plan 2

Spontaneity

Introduction Spontaneity is a process (chemical or physical change) that occurs without any outside intervention The Gibbsrsquo Free energy indicates whether a change in Gibbsrsquo free energy (G) is positive or negative If a process is negative the reaction is spontaneous Spontaneity of a chemical or physical change means the reaction will take place as written left to right This negative change (-G) is termed exergonic If a process is nonspontaneous (endergonic) the reaction will not take place as written but will occur in the opposite direction H is a change in enthalpy and S is change in entropy

G = H -T S (Gibbsrsquo Free Energy Equation) The criterion for spontaneity is

H - TS lt 0 Objective Using thermochemical methods you will measure the enthalpy change that occurs when sodium nitrate is dissolved in water You will also predict the sign of the free energy change ( G) for this process and estimate the minimum value for the entropy change

Concept The process you will examine in this experiment is the dissolving of sodium nitrate NH4NO3(s) NH4NO3(s) == Na+(aq) + NO3

You will measure the heat lost or gained during the dissolving process by using a coffee cup calorimeter Your teacher will explain the technique Then you will calculate the enthalpy change for the process HAfter you have calculated the enthalpy change you will decide whether the process is spontaneous or no spontaneous The sign for G for the process will rest on your decision Finally you should be able to obtain a minimum value for the entropy change S as well as its sign from H and the predicted sign of G

Pre-laboratory assignment1 Provide symbols (where appropriate) and definitions of the following terms

a Enthalpy change

b Entropy change

c Free-energy change

d Spontaneous process

e Nonspontaneous process

2 a How will you decide whether a process is spontaneous in this experiment

b If you were to use this method after you had observed the fate of an ice cube at 25degC what would you conclude about the spontaneity of the following process Why

H20(s) == H20(l)

c The standard enthalpy change for this process is 601 kJmol What is the minimum value for the standard entropy change on the basis of your conclusions about the spontaneity

3 During this experiment you will be required to prepare 100 mL of a 10 M solution of NaNO3 Calculate the mass of NaNO3 (to the nearest tenth of a gram) that will be required

Measuring the heat evolved or absorbed

1 In the Prelaboratory Assignment you calculated the mass of NaNO3 that would be required to prepare 100 mL of a 10 M solution Obtain this mass of NaNO3 using a balance Make sure the pan is protected with a piece of waxed paper

2 Place 100 mL of distilled water in the calorimeter using a clean 100-mL graduated cylinder

3 Measure and record the temperature of this water to the nearest 01ordmC This is the initial temperature (ti)

4 Add the solid NaNO3 to the cup in such a way that none adheres to the side of the cup5 Place the top on the calorimeter immediately and begin stirring

6 Measure the temperature of the solution to the nearest 01ordmC after 30 s and every 30 s thereafter until the temperature attains either a maximum or a minimum value This temperature will be used as the final temperature (tf)

7 Calculate q(system) using 4184 J(g middot ordmC) and 10 gmL for the specific heat and density of the solution and 10 ∙ 101 JC for the heat capacity of the calorimeter

8 Calculate the enthalpy change ΔH from q(system) and the number of moles of NaNO39 Repeat Steps 1 through 8 with a new solution Calculate the mean enthalpy change for

the process10 Pool this value with the data obtained by your classmates and calculate a new mean

enthalpy change

Results

Trial 1 2

Mass of NaNO3 and paper (g) __________ __________

Mass of paper (g) __________ __________

Mass of NaNO3 (g) __________ __________

ti (degC) __________ __________

Temperature (degC) after

30 s __________ __________

60 s __________ __________

90 s __________ __________

120 s __________ __________

150 s __________ __________

180 s __________ __________

210 s __________ __________

240 s __________ __________

tf (degC) __________ __________

q(system) (J) __________ __________

ΔH (kJmol) __________ __________

Mean ΔH (kJmol) ___________

Calculations

Pooled results (Include your own mean ΔH)

__________ __________ __________ __________ __________

Mean ΔH __________

Questions

1 Is this process NaNO3(s) == Na+(aq) + NO3-(aq) spontaneous or

nonspontaneous Why

2 a Use your experimental data and your decision about the spontaneity to calculate a minimum value for the entropy change for the process

b Does the sign of the entropy change predicted by this method agree with the one that you would predict on the basis of the expected change in disorder as solid NaNO3 is dissolved in water Explain

3 Comment on the often-held belief that spontaneous processes must be exothermic

Chemical EquilibriumState goal 402

Lesson plan 1Objective to demonstrate the effect of a concentration stress and a temperature stress on equilibrium An aqueous solution involving the dehydrated-hydrated cobalt complex is produced When the system is heated a color change from pink to blue indicates a shift of equilibrium from left to right When the solution is cooled the color change is from blue to pink indicating a shift from right to left Changing the concentration of reactants results in an equilibrium shift between pink and blue complex ions of cobalt

heat + [Co(H2O)6]Cl2 lt=gt [CoCl2(H2O)2] + 4H2O pink blue

Concentration StressProcedure Wear safety goggles and disposable gloves CoCl2 is toxic

1 Shift of equilibrium to the right Place 20 mL of cobalt(II) chloride solution in a small beaker Slowly add 40 mL of concentrated HCl Note the formation of blue color Use a face shield and gloves when you use concentrated HCl

2 Shift of equilibrium to the left Use half of the solution from step 1 save the other half Add 20 mL of distilled water Note the color change to pink

3 Shift the equilibrium to the left To the remaining solution from step 1 add silver nitrate solution a drop at a time until a precipitate forms Note the formation of a pink color

4 Dispose of the solutions according to the directions in Appendix 5

Reactions

1 Excess C1- causes the formation of more blue tetrachlorocobalt (II) complex2 Excess water shifts the equilibrium to the left and forms more pink hexaaquacobalt(II)

complex3 Silver nitrate removes C1- and the precipitate silver chloride is formed This

precipitation causes the equilibrium to shift to the left and more pink complex is formed

Solutions

1 The cobalt (II) chloride solution of 02 M 26 g of CoC12 per liter of water2 The hydrochloric acid is a concentrated solution3 The silver nitrate solution of 01 M 17 g of AgNO3 per 100 mL of distilled water

(distilled only)Caution Use gloves with silver nitrate

Teaching Tips

1 This demonstration projects well Use Petri dishes on an overhead projector 2 Be sure to use concentrated HC1 in step 1 In addition to adding C1- HC1 has a

dehydrating effect3 Have students make predictions of the effect on equilibrium before each part of the

demonstration

QUESTIONS FOR STUDENTS

1 What is the effect of adding a common ion to a system in equilibrium2 Explain what happened in each part of the demonstration3 What might be another way to shift equilibrium to the right4 Blue colors are usually associated with hydrated compounds Why does the hydrated

cobalt complex have a pink color

Temperature Stress

Procedure

Wear safety goggles and disposable plastic gloves CoC12 is toxic

1 Place 1000 mL of CoC12 solution in a 250-mL beaker2 Add concentrated HC1 until the solution changes from pink to blue Use a face shield

and gloves when you use concentrated HC1 3 Divide the solution into three smaller beakers and treat them as follows

a Place one beaker on a hot plateb Place one beaker in an ice bathc Leave one beaker at room temperature as a standard

4 After a few minutes show that the heated sample has turned a darker blue and that the cooked sample has turned a light pink

Reactions

1 Addition of heat causes a shift of equilibrium toward products the blue solution 2 Cooling causes a shift of equilibrium to the left the pink hydrated complex

Solutions

1 The CoC12 solution of 04 M Dissolve 52 g per 100 mL of water2 The HC1 solution is concentrated

Teaching Tips

1 As indicated in the equation you may have to add quite a bit of HCl to get the formation of the blue complex

2 The clue color is due to the tetrachlorocobalt(II) complex and the pink color is due to the hexaaquacobalt(II) complex

3 For an interesting variation heat 150 mL of CoC12 solution until it turns blue Fill a large test tube with this solution and immerse it halfway into a beaker that contains crushed ice and salt The bottom part of the test tube will turn pink

QUESTIONS FOR STUDENTSrsquo

1 Write an equation for the equilibrium system2 Why was it necessary to add HC1 to establish equilibrium3 How does heating shift the equilibrium4 What do you think will happen to the equilibrium system if you add water

___________________________________________________________________

Acids and BasesState goal 404Lesson plan 1

Acids and Bases (electrolytes)Objective To demonstrate the extent of dissociation of strong and weak acids and bases and to relate equilibrium concepts to acid and base dissociation

Needed 01 M solutions of HCl HNO3 HC2H3O2 H2SO4 H3PO4 NaOH NH4OH Ca(OH)2 and conducting apparatusNote Strong acids and bases completely dissociated and are strong electrolytes

Dissociation Ions in solution (100 or few)

1 HCl(aq)

2 HNO3(aq)

3 HC2H3O2 (aq)

4 H2SO4(aq)

5 H3PO4(aq)

6 NaOH(aq)

7 NH4OH(aq)

8 Ca(OH)2(aq)

1 After discussing in class which acids and bases are strong and which are weak you are to predict the dissociation of the following acids or bases (by writing the dissociation as above) and to relate which of the following compounds demonstrate equilibrium a) HClO4(aq) b) HF(aq) c) KOH(aq) d) Sr(OH)2(aq)2 Which solutions in the above demonstration (1-8) produced the greater H+ (H3O+)3 Which solutions in the above demonstration (1-8) produced the greater hydroxide ion concentration

Lesson plan 2

Antacids vs Acids Objective Students will measure the degree that antacids are able to neutralize excess stomach acid Materials

White vinegar (5 acetic acid) Sodium bicarbonate (NaHCO3) Various antacids Clear plastic cups Medicine dropper or pipette Mortar and pestle Indicator phenolpthalein Water Teaspoon measurer Paper towels

Procedure

1 Grind the antacid into a fine powder with the mortar and pestle 2 Keep the different antacids separate by labeling your paper towel Make sure not to

mix the powders from the different antacids together 3 Put 2 teaspoons of the vinegar in a plastic cup This is to simulate the excess stomach

acid4 Drop 5 drops of the indicator to the vinegar and observe the color (should be clear)5 Drop very small amounts of the baking soda (sodium bicarbonate) to the vinegar

until the indicator turns pinkish-red This means that the system is neutral Make sure to keep track of how much baking soda yoursquove added so you know how much it took to neutralize the system

6 Repeat the process with different antacids in place of the baking soda Be sure that you make a new ldquoexcess acidrdquo and indicator solution before repeating the process with the different antacids

7 When you are finished with the baking soda and the various antacids compare your results

Follow-up questions1 How did your numbers compare Which is the better neutralizer How does your data prove

this2 Identify some of the ingredients in the various antacids Which ingredients neutralize acid

Which ingredients are common between brands3 Write and balance the equation for the neutralization of acetic acid (HC2H3O2) by baking

soda (sodium bicarbonate)

REVIEW OF GOALS USING THE STATE CHEMISTRY EXAM REFERENCE TABLE

Objective to use the State Exam Reference Table and student knowledge to practice for the State Chemistry Exam to review familiarity with the reference table

1 How many molecules are in 20 moles of water

2 Calculate the amount of heat absorbed to melt 360 g of ice at 0 OC to water at 0 OC

3 Covert 25 OC to K

4 Convert 411 nm to m

5 What is the charge on one electron in Coulombs What do you think would be the charge on one proton

6 Calculate the pressure of 0700 mol of a gas at 27 OC that is contained in a volume of 150 L

7 Calculate the mass of 240 L of ammonia gas at STP

8 Predict the products of the decomposition of 1) carbonic acid and 2) copper (II) carbonate

9 Will the following single replacement reactions take place If so write and balance1) zinc + hydrochloric acid2) tin + aluminum chloride3) chlorine + sodium bromide

10 Indicate by giving the formula of the precipitate that allows the following double replacement reactions to take place

1) barium nitrate + sodium carbonate2) iron (III) chloride + potassium hydroxide

11 What is the solubility (g100g water) of the solid NH4Cl at 70 OC As the temperature increases the solubility of gases tend to increasedecrease (circle the correct answer)

12 Uranium-238 decays to thorium-234 to become more stable what particle is emitted Thorium-234 decays to protactinium-234 (Pa) to reach some stability what particle is emitted

13 A Using the standard reduction table which half-reaction is more likely to undergo reduction in the present of the other in an electrochemical cell

Ag+ + e Ag Cd2+ + 2e CdB What is the standard cell potential (total voltage) of the electrochemical cell

14 Which gas effuses the faster He or SO2 How much faster

15 A student determined the density of silver to be 990 gcm3 She looked up the accepted value of silver on the state exam Reference Table to calculate the Error What was her Error

16 Calculate the molarity (M) of 440 g of NH4Cl dissolved in enough water to make a 775 mL solution

17 Calculate molality (m) of a solution in which 250 g of NaCl are dissolved into 1500 grams of water

18 500 g of silver metal are heated from 250 OC to 410 OC When the silver is placed in water the silver releases 192 J of heat energy Calculate the specific heat (Cp) of silver See page vi of state exam Reference Table for the equation

19 Calculate the heat absorbed when 500 g of ice at 0 OC is converted to water (melted) at 0 OC

20 FILL IN THE BLANK In the Bohr model of the hydrogen atom when electrons

absorb enough energy electrons________________________ When electrons fall back

to the original energy level electrons give off this energy in the form of _____________

If an electron falls from n=3 to n=2 the wavelength of light emitted is_______________

21 In the electromagnetic spectrum does violet light or red light have the longer wavelength the greater frequency See vi of reference table for the equation showing the relation between frequency (v) and wavelength ( λ )

Additional Chemistry teacher lesson plans are found at wwwgeocitiescomchem416 Click Lesson Plans for Teachers

Ed Ray

Law of Definite Composition

Rusting as a Chemical Reaction

Chemical Equations

Citrus Batteries

Ions in Solution

Mixtures as Solutions or Colloids and the Tyndall Effect

Stoichiometry Theoretical Mass vs Experimental Mass

Mass of beaker

Mass of zinc acetate

States of Matter

State goals 302 401

Lesson plan 1

The Process of Sublimation and Deposition

Temperatures and Reaction Rates

Antacids vs Acids