Math Review for ChemistryKey Ideas

Matter is classified as a pure substance or as a mixture of substances. (3.1q)

The three phases of matter (solids, liquids, and gases) have different properties. (3.1kk)

A pure substance (element or compound) has a constant composition and constant properties throughout a given sample, and from sample to sample. (3.1r)

Elements cannot be broken down by chemical change. (3.1u) Mixtures are composed of two or more different substances that can be

separated by physical means. When different substances are mixed together, a homogeneous or heterogeneous mixture is formed. (3.1s)

The proportions of components in a mixture can be varied. Each component in a mixture retains its original properties. (3.1t)

Differences in properties such as density, particle size, molecular polarity, boiling point and freezing point, and solubility permit physical separation of the components of the mixture. (3.1nn)

A solution is a homogeneous mixture of a solute dissolved in a solvent. The solubility of a solute in a given amount of solvent is dependent on the temperature, the pressure, and the chemical natures of the solute and solvent. (3.1oo)

Energy can exist in different forms, such as chemical, electrical, electromagnetic, thermal, mechanical, and nuclear. (4.1a)

Heat is a transfer of energy (usually thermal energy) from a body of higher temperature to a body of lower temperature. Thermal energy is the energy associated with the random motion of atoms and molecules. (4.2a)

Temperature is a measurement of the average kinetic energy of the particles in a sample of material. Temperature is not a form of energy. (4.2b)

The concepts of kinetic and potential energy can be used to explain physical processes that include: fusion (melting), solidification (freezing), vaporization (boiling, evaporation), condensation, sublimation, and deposition. (4.2c)

A physical change results in the rearrangement of existing particles in a substance. A chemical change results in the formation of different substances with changed properties. (3.2a)

Chemical and physical changes can be exothermic or endothermic. (4.1b) The structure and arrangement of particles and their interactions determine the physical state of a substance

at a given temperature and pressure. (3.1jj) The placement or location of elements on the Periodic Table gives an indication of physical and chemical

properties of that element. The elements on the Periodic Table are arranged in order of increasing atomic number. (3.1y)

Elements can be classified by their properties and located on the Periodic Table as metals, nonmetals, metalloids (B, Si, Ge, As, Sb, Te), and noble gases. (3.1v)

Elements can be differentiated by their physical properties. Physical properties of substances, such as density, conductivity, malleability, solubility, and hardness, differ among elements. (3.1w)

Elements can be differentiated by chemical properties. Chemical properties describe how an element behaves during a chemical reaction. (3.1x)

Some elements exist in two or more forms in the same phase. These forms differ in their molecular or crystal structure, and hence in their properties. (5.2f)

1

Math Review for ChemistryMatter

Do Now: Complete the following Pre-test. Put T for true statements and F for false statements in the space provided.

____1. Matter is anything that has mass.

____2. A spaceship ceases to be matter when it is in space because it has no weight.

____3. Air can be weighed.

____4. Heat has weight.

____5. Both air and heat are matter.

____6. Matter takes up space.

____7. Air occupies space.

____8. Light takes up space.

____9. Light is matter.

____10. Matter can be in different shapes.

____ 11. Matter can be in different phases.

____12. Water has no definite shape therefore it is not a matter.

____13. A solid has a definite shape.

____14. You cannot change the shape of a solid.

____15. You can compress water to force it to occupy less space.

____16. A glass is inverted over a basin of water and slowly inserted into the water. However,

the water does not enter the glass. This experiment proves that air takes up space.

____17. Air will expand to fill the space available.

____18. Matter can exist in three states: solid, liquid and gas.

____19. Iron combines with oxygen in moist air to form iron oxide, or rust. This change is

called a chemical change.

____20. When water changes to steam it undergoes a chemical change.

Matter vs. Not Matter

2

Math Review for Chemistry

Can you recognize matter when you see it? What makes matter different from that which is not matter? A light bulb, for example, is matter. The electricity that makes it glow is not. What is the difference? All matter has certain characteristics in common that separate it from whatever is not matter. Can you tell which is which? Get together with your lab group and try. You will be given a card with a list of six items. Three are matter and three are not.

1. Try to classify the items on the card properly. Write your conclusions in the table below.

MATTER NOT MATTER

2. Describe the characteristics all the items you classified as MATTER have in common that make them different from the items you classified as NOT MATTER.

Matter- Anything that has mass and volume (takes up space)

1. An element is the simplest form of matter.• It cannot be decomposed• Elements are made up of tiny particles called atoms• There are 7 diatomic elements

2. A compound is a substance made up of two or more elements in a fixed proportion• compounds are made up of particles called molecules

3. A mixture is a combination of two or more substances (elements or compounds) • It can be separated into components by physical methods• It can be homogeneous or heterogeneous

Matter Activity

3

Math Review for ChemistryStation Number/

Identity of SubstanceDescription/Observations Classification

(Element,Compound,

Homogeneous Mixture, Heterogeneous Mixture)

How do you know?

1

2

3

4

5

6

7

8

9

10

11

4

Math Review for Chemistry12

13

14

Questions:

1. How could you tell a substance is an element?

2. What phases can elements be in?

3. How could you tell a substance is a compound?

4. What phases can compounds be in?

5. How could you tell a sample is a mixture?

6. What phases can mixtures be in?

7. How do you know the difference between a homogeneous and heterogeneous mixture?

5

Math Review for Chemistry

6

MatterAnything that has mass and volume (takes up space)

PURE SUBSTANCES (each piece looks the same

– PURE!)-each piece has exact same

composition.

MIXTURES (each piece is different – not pure)

Can NOT be separated by physical means

CAN be separated by PHYSICAL means

ELEMENT (simplest form of matter)

Example: Na, Cl2

HETEROGENEOUS MIXTURE (not uniform throughout— a pattern)

Example: Italian dressing, concrete, soil, chocolate chip cookie

Hetero = opposite

HOMOGENEOUS MIXTURE (uniform throughout—distinct pattern)

Example: saltwater, iced tea

Homo = same

COMPOUND or MOLECULE(2+ different elements chemically combined)

Example: NaCl (table salt), H2O (water)

Can NOT be separated by chemical means

Separated by chemical means,

only

Same composition throughout

Different composition throughout

Particle Diagram

Particle Diagram

Particle Diagram

Particle Diagram

Math Review for ChemistryParticle Diagrams of Matter

Particle diagrams are used to illustrate states and forms of matter. Typically, a particular type of atom is shown as a small circle of one color or shade.

A diagram of an element would contain only one type of atom.

A compound would contain two or more types of atoms attached in a fixed ratio

A mixture would contain one or more elements and one or more compounds.

Check your understanding:

IDENTIFY THE FOLLOWING AS A PURE ELEMENT, PURE COMPOUND OR MIXTURE OF ???

___________ __________ ____________ __________ __________

7

Math Review for Chemistry

8

Math Review for ChemistryElements, Compounds, and Mixtures Notes

There are 2 types of PURE SUBSTANCES. They can be either an element or a compound.1.) Element : It is the simplest form of matter that can exist under lab conditions.

Elements cannot be separated into simpler substances. They are represented by a symbol; ONE Capital Letter. (Each capial letter represents one element.)

Sometimes a lowercase letter is used as well. Elements are shown on the Periodic Table Elements can be classified as metals (left of staircase), nonmetals (right of staircase), or metalloids. Transition metals, groups 3-12, can create colored compounds and solutions. • There are some elements (only 7!) that exist in nature only as diatomic elements.

Br2, I2, N2, Cl2, H2, O2, F2

That means there are two atoms of one kind stuck (bonded) together so you should always use a co-efficient of 2 when you see them in an equation!

Examples of particle diagrams that would represent diatomic elements:

2.) Compound: Two or more elements chemically combined with each other. Compounds can be separated into simpler substances. A compound has a fixed composition. It is always the same. Formulas for compounds are written in a certain way.

EXAMPLES: H2O CO2 NaCl The little numbers directly following an element symbol are called subscripts. This

tells you how many atoms of that element are in the compound.EXAMPLES: H2O CO2 NaCl

(2 H’s and 1 O) (1 C and 2 O’s) (1 Na and 1 Cl) A common mistake by students such as yourself happens in compounds like CO2. The 2 goes ONLY

TO THE O… NOT TO THE C (as shown above in the formula and below in the picture.) We can draw particle diagrams of these three compounds as follows:

H2O CO2 NaCl Compounds are made up of molecules (a specific ratio of chemically combined atoms).

A mixture is a blend (physical change) of two or more substances. Homogeneous Mixtures are uniform throughout

Examples: salt in water, air Heterogeneous Mixtures are non-uniform

Examples: chunky chicken soup, dirt in water Homogeneous and Heterogeneous are both relative terms. This means that some of your answers

will depend on your prior experiences and knowledge. As long as you can defend/explain why you answered your question the way you did, it is acceptable.

Na + S is a mixture. Likewise Na2S + KCl is a mixture

9

Math Review for ChemistryMetals, Nonmetals, and Metalloids Activity

Directions: For each element, write observations and given details and determine if they are metals, nonmetals, or metalloids (semimetals). Then complete the rest of the table.

Observations/Details M, NM, or SM

Element Period Group

1

2

10

Math Review for Chemistry3

4

5

6

7

8

9

10

11

12

13

14

11

Math Review for ChemistryMetals

Nonmetals

Metalloids

12

Math Review for ChemistryMetals and Groups/Periods Questions

1. Which three groups of the Periodic Table contain the most elements classified as metalloids (semimetals)? A) 1, 2, and 13 B) 2, 13, and 14 C) 14, 15, and 16 D) 16, 17, and 18

2. Which elements have the most similar chemical properties?A) K and Na B) K and Cl C) K and Ca D) K and S

3. The metalloids that are included in Group 15 are antimony andA)N B) P C) As D) Bi

4. Which sequence of atomic numbers represents elements which have similar chemical properties? A) 19, 23, 30, 36 B) 9, 16, 33, 50 C) 3, 12, 21, 40 D) 4, 20, 38, 88

5. Which group contains elements composed of diatomic molecules at STP? A) 11 B) 2 C) 7 D) 17

6. On the Periodic Table, an element classified as a semimetal (metalloid) can be found inA) Period 6, Group 15 B) Period 2, Group 14 C) Period 3, Group 16 D) Period 4, Group 15

7. Which element is considered malleable? A)gold B) hydrogen C) sulfur D) radon

8. Which element is malleable and conducts electricity? A) iron B) iodine C) sulfur D) phosphorus

9. Which element is malleable and ductile? A) S B) Si C) Ge D) Au

10. Which element is brittle and does not conduct heat or electricity? A) S(s) B) Mg(s) C) Al(s) D) K(s)

11. Which element is an active nonmetal? A) Neon B) oxygen C) zinc D) chromium

12. Which characteristics describe most solid nonmetals?A) They are malleable and have metallic luster. C) They are brittle and have metallic luster.B) They are malleable and lack metallic luster. D) They are brittle and lack metallic luster.

13. Which element is a metalloid?A) Al B) Ar C) As D) Au

14. The element arsenic (As) has the properties ofA) metals, only B) nonmetals, only C) both metals and nonmetals

15. Which element is not a metalloid?A) arsenic B) boron C) silicon D) sulfur

16. Which compound forms a green aqueous solution?A) RbCl B) CaCl2 C) NiCl2

13

General Chemistry Unit 2: Matter

14

General Chemistry Unit 2: MatterMatter Practice

Directions: After each statement below, choose the letter of the word that applies from the list below.

a. matter e. compoundb. substance f. heterogeneous mixturec. mixture g. homogeneous mixtured. element

_____ 1) cannot be chemically decomposed

_____2) components can be combined in any ratio

_____ 3) components must be combined in a specific, fixed ratio that can never change

_____ 4) has mass and volume

_____5) chemically combined to produce new substance with totally new properties

_____ 6) substances are physically combined, unevenly spread throughout

_____7) substances are physically combined, evenly spread throughout

_____ 8) combining substances where each substance retains its individual properties

_____ 9) manganese

_____ 10) Al2(SO4)3

_____ 11) sand in water

_____ 12) physically combined, physically separated

_____ 13) since the substances retain their individual properties, they can be separated based on their

unique physical properties

_____ 14) can’t be physically decomposed, but can be chemically decomposed

15

General Chemistry Unit 2: MatterMatter Practice

Classify each of the following with the combination of terms listed below.pure substance – element mixture – homogeneouspure substance – compound mixture – heterogeneous

1. HCl (aq) 2. sugar (C11H22O11) 3. KBr (s) 4. Soil

5. Cl2 (g) 6. water 7. CH2(OH)2 (aq) 8. Sodium

9. Hg (l) 10. iron oxide 11.NH3 (l) 12. salt water

13. Matter that is composed of two or more different elements chemically combined in a fixed proportion is classified as

(1) a compound (2) an element (3) a mixture (4) a solution

14. A compound differs from an element in that a compound(1) is homogeneous(2) has a definite composition(3) has a definite melting point(4) can be decomposed by a chemical reaction

15. A compound differs from a mixture in that a compound always has a(1) homogeneous composition(2) maximum of two elements(3) minimum of three elements(4) heterogeneous composition

16. A heterogeneous material may be(1) an element(2) a compound(3) a pure substance(4) a mixture

17. Which statement is an identifying characteristic of a mixture?(1) a mixture can consist of a single element(2) a mixture can be separated by physical means(3) a mixture must have a definite composition by weight(4) a mixture must be homogeneous

18. Which must be a mixture of substances?(1) solid (2) liquid(3) gas (4) solution

16

General Chemistry Unit 2: Matter

19. Which substance can be decomposed by chemical means?(1) aluminum (2) octane (3) silicon (4) xenon

20. Which substance can be decomposed by chemical means?(1) ammonia (2) oxygen(3) phosphorus (4) silicon

21. Which substance can not be broken down by a chemical reaction?(1) ammonia (2) argon (3) methane (4) water

22. Two substances, A and Z, are to be identified. Substance A can not be broken down by a chemical change. Substance Z can be broken down by a chemical change. What can be concluded about these substances?

(1) Both substances are elements.(2) Both substances are compounds.(3) Substance A is an element and substance Z is a compound.(4) Substance A is a compound and substance Z is an element.

23. Which terms are used to identify pure substances?(1) an element and a mixture(2) an element and a compound(3) a solution and a mixture(4) a solution and a compound

24. Two different samples decompose when heated. Only one of the samples is soluble in water. Based on this information, these two samples are

(1) both the same element(2) two different elements(3) both the same compound(4) two different compounds

25. Tetrachloromethane, CCl4, is classified as a(1) compound because the atoms of the elements are combined in a fixed proportion(2) compound because the atoms of the elements are combined in a proportion that varies(3) mixture because the atoms of the elements are combined in a fixed proportion(4) mixture because the atoms of the elements are combined in a proportion that varies

17

General Chemistry Unit 2: MatterDrawing Particle Arrangements

Draw a diagram of a:

pure diatomic pure diatomic mixture of mixture of mixture ofelement compound two elements an element & two diatomic

a compound elements &a compound

1.) In terms of composition/type of atoms, what is the difference between a monatomic element, a diatomic element, and a diatomic compound?

2.) Use the following key for parts a-c. = element X = element Z

a.) 8 atoms of element X in gaseous form b.) 4 molecules of compound X2Z in liquid form

c.) Homogeneous mixture of element Z with element X (10 atoms of each element).

18

General Chemistry Unit 2: MatterSeparating Mixtures

Since mixtures are made by physically combining 2 or more pure substances together, we use physical techniques to separate them. The technique used depends on what phase or state of matter the components are.

1. Fitration-solid and a liquid2. Phase change-distillation, evaporation, etc. 3. Separatory funnel-two immiscible liquids 4. Various physical means such as magnet, tweezers, sieve -two solids5. Chromatography – density and particle size differencesSeparation Apparatus Type of Separation

(Physical or Chemical) Description of

TechniqueWhat types of

Matter will it separate?

Filtration

PHYSICAL

Undissolved particles remain on filter paper (filtrate flows through filter paper)

HETEROGENEOUS mixtures (ex: sand

water)

*Can also centrifuge

Watch Glass Evaporation

PHYSICAL

Separate solute (dissolved solid) from solvent (liquid) by boiling solution

Solute escapes Very limited

precision

HOMOGENEOUS mixture (solution)

19

General Chemistry Unit 2: Matter

Distillation

PHYSICAL

Separate solute from solvent by boiling solution and recondensing in receiving flask (both solute and solvent captured)

Separate 2 or more liquids with different boiling points

HOMOGENEOUS (can use to remove

impurities from water)

Chromatography

PHYSICAL

Separates particles based on:

1) size2) solubility

HOMOGENEOUS

20

General Chemistry Unit 2: MatterCheck your Understanding: For each picture below:

a) Identify the separation technique from the list above. b) Select the property that allows for the technique to work, from among these choices:

1. Differences in particle “attractiveness” or “electrical stickiness” of the mixture components, allowing them to be separated when solvent and some other medium (like paper) “compete” for the mixture components.

2. Differences in particle size of the mixture components.

3. Differences in particle boiling points of the mixture components.

Technique: ___________

Property allowing it to work: # ___

Technique: ________________ Technique:______________

Property allowing it to work: # ____ Property allowing it to work: #____

21

General Chemistry Unit 2: MatterPhases

Almost all substances can be made to change between the 3 phases, simply by altering the temp.The classification of matter into solids, liquids and gases is termed as physical classification of matter.

Characteristics of solids Solids maintain their volume independent of the size or shape of the container in which they are

placed in. Solids are rigid and have definite shape. Solids diffuse very slowly compared to liquids and gases, due to close packing Solids are incompressible. Most solids melt on heating, and some sublimate. Solids have very high mass to volume ratio or density compared to liquid or gases. Solid molecules cannot move past one another. Solids have strong Intermolecular forces of attraction.

Characteristics of liquids Moderate forces of attraction exist between the molecules of a liquid. The molecules in a liquid are in a state of random motion although the extent is much smaller in

comparison to gases. The liquid molecules can flow past one another. The average Kinetic energy of the molecules in a liquid is proportional to the temperature.

Characteristics of gases Gases maintain neither volume nor shape and completely fill the container in which they are

introduced. Gases expand when heated. Gases diffuse rapidly; we can smell perfume even when applied at a distance very fast. Gases are highly compressible; if pressure is increased then volume decreases. Almost all gases except a few are colorless. Gases flow easily, moving past one another. Gases have the weakest intermolecular forces of attraction.

Directions: Using the boxes provided below as your container, place six circular molecules in each container representing the given phase. Then on each line with the arrow label which phase change is occurring.

SOLID (s) LIQUID (l) GAS (g)

22

General Chemistry Unit 2: Matter

PracticeFill in the table below.

Solid Liquid GasShape

(Has a fixed shape or takes the shape of the

container)Volume

(Has a fixed volume or takes the volume of the

container)Density

(high or low)

Particle arrangement (rigid or free)

Attraction(particles are highly

attracted and close or weakly attracted and

spread out)

23

General Chemistry Unit 2: MatterHeating Curve Worksheet

Below is a diagram showing a typical heating/cooling curve for water. It reveals a wealth of information about the structure and changes occurring in water as it is heated or cooled through all three phases of matter at different temperatures. At the top of the diagram are pictures representing the typical particle arrangement as substances change through their states.

1. There is something clearly wrong about the particle spacing in the pictures at the top. What is it? (Hint… the pictures were drawn for most materials, not for water specifically).2. Identify by letter (A-E) in which section the following are found:

a. _______ Freezing (if cooling) b. _______ Particles farthest apart

c. _______ Boiling d. _______ Particle motion is most restricted

e. _______ Heat of fusion f. _______ All areas where energy change is potential only

g. _______ Heat of vaporization h. _______ All areas where particles move past each other

i. _______ Least kinetic energy j. _______ All areas where kinetic energy is changing

k _______ most potential energy l. _______ All areas where phase changes occur

m. _______ All areas in which the heat is making the particles move faster

n. _______ All areas in which the heat is breaking the attractions or bonds between particles

o. _______ All areas in which the particles are not changing their speed24

General Chemistry Unit 2: MatterNow try an unlabeled heating curve for water without pictures and see how well you do!

1. First identify the sections where the following phases are found:

a. _______ gas b. _______ solid c. _______ liquid

d. _______ solid and liquid e. _______ liquid and gas

2. Identify by letter (A-E) in which section the following are found:

a. _______ Freezing (if cooling) b. _______ Particles farthest apart

c. _______ Boiling d. _______ Particle motion is most restricted

e. _______ Heat of fusion f. _______ All areas where energy change is potential only

g. _______ Heat of vaporization h. _______ All areas where particles move past each other

i. _______ Least kinetic energy j. _______ All areas where kinetic energy is changing

k _______ most potential energy l. _______ All areas where phase changes occur

m. _______ All areas in which the heat is making the particles move faster

n. _______ All areas in which the heat is breaking the attractions or bonds between particles

o. _______ All areas in which the particles are not changing their speed

25

Heating / cooling curve for water

General Chemistry Unit 2: MatterPhysical and Chemical Properties

Do Now: Read the following and fill in the information:

Properties of MatterPhysical Observable or measurable porperties

Ex) hardness, color, smell, mass, melting pointChemical Describes how a substance reacts OR does not react with

other substance(s)Ex) Copper reacts with Nitric Acid, Cu does not react with hydrochloric acid (HCl)

Identify the following as being physical or chemical properties.

________________1. The mass of copper wire is 255 g.

________________2. The boiling point of ethyl alcohol is 77°C.

________________3. Baking soda reacts with vinegar to make carbon dioxide gas.

________________4. The density of mercury is 13.6g/mL.

________________5. The solubility of sodium chloride in water is 40g/100mL of water.

Physical and Chemical Changes

Properties of Matter Changes in MatterPhysical Observable or measurable properties

Ex) hardness, color, smell, mass, melting pt.

Altering a substance without changing its composition or properties; the original material can be recovered. (Still the same substance but in a different form)

Chemical Describes how a substance reacts OR does not react with other substance(s)Ex) Copper reacts with Nitric Acid, Cu does

not react with hydrochloric acid (HCl)

A new substance is made that has a different composition and properties; the original material can sometimes (not usually) be recovered, but usually only with great

26

General Chemistry Unit 2: Matterdifficulty. (New substanced formed)

27

General Chemistry Unit 2: MatterReactions

In order to keep track of how things are changing. We have to look at the before and the after. Chemists do this by writing an equation, similar to what you have done in math class. The only real difference, is that you replace the = with !

Some important vocab: An equation describes a chemical change or reaction. The equation shows substances which react

with each other once mixed to form other substances. Reactants (the substances that we start with, or in other words that react) are on the left side of

the equation. Products (the substances that we end with, or in other words are produced) are on the right side

of the equation. Reactants and products are separated by an arrow. It shows the direction of the equation. System is another word for reaction that is often used by chemists.

For example:I am starting with Na and Cl and I want to change it into NaCl. We can do a reaction to make this happen and we can record the change with an equation.

2Na + Cl2 2 NaCl + heatHow many different substances are described on the “left side” of the equation? 1) How many different substances described on the “right side” of the equation? 2) What does this tell me? I can look at an equation to see if a change is chemical or physical. In this

case, since a new substance is formed, it is a chemical change.

***Note that the number and kind of atoms on the left side of the equation equal the number and kind of atoms on the right side of the equation. Only the arrangement of the atoms has changed in going from reactants to products. The equality of atoms or matter on either side of a chemical equation is called a balanced equation; it illustrates the principle of the Conservation of Matter.

Conservation of Matter: Matter can neither be created or destroyed , but the atoms in the reactants can become rearranged in a chemical change. Weighing the system before and after a chemical change is a way to prove this.

Note: Conservation of Matter is also called Conservation of Mass. They are interchangable terms. To see if an equation has conservation of matter or mass, we look for the one that is balanced.

For example:Pick the change (equation) that correctly shows a conservation of mass:

1) NaCl Na + 2 Cl2) 2 NaCl 2 Na + Cl3) NaCl 2 Na + Cl2

4) 2 NaCl 2 Na + Cl2

28

General Chemistry Unit 2: MatterExo vs. Endothermic Changes

Just as there is a Law of Conservation of Matter, there is a Law of Conservation of Energy.

Law of Conservation of Energy- Energy can neither be created or destroyed.

Usually there is an energy change involved in either a chemical change or a physical change.

Reaction How I Know Direction of Heat Flow

Type of Energy Change

Reactant or Product (in Equation)

Requires Heat

Feels cold around the

change

From the surroundings

into the system

Endothermic Reactant

Releases Heat

Feels hot around the

change

From the system into the surroundings

Exothermic Product

Check your understanding:State whether the following reactions or processes are physical or chemical changes and if they are exothermic or endothermic:

1. Burning charcoal glows bright red until it turns to ash

2. To convert one gram of ice to water, 334 J of heat must be added.

3. SO3(g) + H2O (l) H2SO4(aq) + heat

4. CaCO3(s) + heat CaO(s) + CO2(g)

5. Neutralization of a strong acid with a base gives a warm solution.

6. Barium hydroxide mixed with ammonium chloride yields ammonia gas and the flask gets cold.

7. When heated to a high temperature, iron melts.

8. Water freezes to ice at 0 degrees Celsius.

29

General Chemistry Unit 2: MatterChanges Written as Equations

Do Now: Complete the chart to the best of your ability.

Situation Type of Change (P or C)

Explanation (Write a sentence.)

Cooking an egg

Digesting your lunch

Mixing the ingredients for a

cakeRusting of a nail

Dew forming on the lawn

Melting ice off a windshield

Combustion (burning) of

gasolinePurifying salt water

by evaporation

CO2 (s) CO2 (g)

H2O (g) H2O (l)

H2ONaCl (s) NaCl (aq)

30

General Chemistry Unit 2: MatterUnit 2 Matter: General Chemistry Review

ELEMENTS, COMPOUNDS, AND MIXTURES

1. Matter is anything that has a mass and takes up space. An element is the simplest form of matter which cannot be broken down any further. Elements are listed on Table S and the periodic table. Their symbols start with an uppercase letter.

a. Which of the following is not matter? _____________________

Magnesium Calcium Carbonate Salt water Heat

b. Which of the above is an element? _____________________

2. Compounds are composed of two or more elements. They can only be decomposed chemically. Elements and compounds are also known as substances.

a. Which of the choices in number one was a compound? ________________________

b. How can compound be broken down? __________________________________________________

c. Which of the choices in question one are substances? ______________________________________

3. Mixtures are physical combinations of two or more substances (elements and/or compounds). Mixtures can be homogeneous (completely mixed, cannot see the parts) or heterogeneous (unevenly mixed, can see the parts). Mixtures can be separated by physical means.

a. Label each as homogeneous or heterogeneous:

Sand: ____________________ Brass: ______________________________

Milk: ____________________ Oil and water: ________________________

4. Compounds must be separated chemically but mixtures can be separated easily using physical methods.

a. Match each method with its name.

Distillation Separated by differences in particle size

Filtration To pour off the top layer of an uneven mixture

Decant Separated by differences in boiling point.

b. Which of the above processes only work if the mixture is heterogeneous? _____________________

31

General Chemistry Unit 2: Matterc. Label the following as element (E), compound (C), or mixture (M).

__________________________________________________________________________________________

SOLIDS, LIQUIDS, AND GASES

5. A solid has a definite shape and volume. Solids are arranged in a geometric pattern. Liquids have a definite volume but take the shape of the container they are in. Gases have an indefinite shape and volume; they take the shape and volume of the container. Gases are easily compressed.

a. Draw particle diagrams for a solid, liquid, and a gas using at least 5 particles:

b. Which has a definite shape?

HCl(g) H2O(l) Cu(s)

c. Which has a definite volume?

LiF(g) Br2(l) Mg(s)

32

General Chemistry Unit 2: Matter6. Vapors are the gas phase of substances that are normally solid or liquid at room temperature.

a. Which can be a vapor?

Carbon dioxide ______ Water _____ Oxygen _____

__________________________________________________________________________________________

CHANGES IN THE LAB

7. Physical changes are changes where the substance retains its properties. Chemical changes will make substances change into new substances and change properties.

a. Label the following as physical (P) or chemical (C) properties:

Texture ____ flammability ____ boiling point: ____

Odor ____ color ____ chemical composition: ____

b. Label the following as physical (P) or chemical (C) changes:

Corrosion: ____ melting: ____ mixing: ____

Freezing: ____ cutting: ____ decaying: ____

8. In chemical reactions mass is conserved.

a. Can you form or destroy matter? _______________________________________________________

b. Mass of reactants is ______________ mass of products. (Greater than, Equal to, or less than?)

METALS, NONMETALS, AND METALLOIDS

9. Metals are elements on the left side of the staircase on the periodic table. They have 1-2 valence electrons, which they tend to lose to form cations. Metals are lustrous, malleable, ductile, and good conductors of heat and electricity.

a. Define lustrous.

b. Define malleable.

c. Define ductile.

d. Circle the metal: H P Cu S

33

General Chemistry Unit 2: Matter10. Nonmetals are elements on the right side of the staircase on the periodic table. They have 4-8 valence electrons, which they tend to gain to form anions and fill their octet. Nonmetals are dull, brittle, and poor conductors of heat and electricity.

a. Circle the nonmetal: C Mg Na Au

b. Why is hydrogen considered to be a nonmetal?

11. Metalloids are elements that touch the staircase on the periodic table. They have properties of both metals and nonmetals.

a. Most elements on the periodic table can be classified as metal, nonmetal, or metalloid?

b. Circle the metalloid: S Si Se Sr

c. Circle the element that is lustrous: Na N Rn Ne

d. Circle the element that is malleable: Mg C Ar H

e. Circle the element that is dull: S Sc Sr Sn

f. Circle the best conductor: C Cl Cu He

g. Circle the element that has properties of both metals and nonmetals: Ge Ga

34