Name: ____________________________________ Period:chemcast.weebly.com/.../chemical_reactions_packet_w_dr_lab.docx · Web viewwarm up nomenclature + sol rules. Gave packet. Did page

Name: ____________________________________ Period: _________

Chemical ReactionsIdentifying, writing and balancing reactions; Predicting products of reactions,

Factors that affect reaction rates

Entire packet will be due on the test day. Keep up with daily assignments; they will be checked regularly for homework grades.

Date Topic Homework (you write in the assignment for the night)

Tuesday 3/22 warm up nomenclature + sol rules. Gave packet. Did page 2 intro chem. Rxns and page 3 #1 as example.

page 3 #2-4

Wednesday 3/23 warm up nom quiz formula + sol rules. Went over pg 3 hmwk (many mistakes!) Learned bal eq pg 6. Did pg 7 #1 as example

page 7

Thursday (late start)

3/24 nom quiz 3. Page 7 hmwk checked on qwizdom none

Friday 3/25 2 TAKS warm ups. Card sort for rxn types. Kids make names/descriptions. Debriefed whole group. Did practice pg 5 in class whole group

page 8 #1-5

Monday 3/28 2 TAKS warm ups. Students entered hmwk into Qwizdom to check. Did SR rxn pg 10 #5 together.

assigned 1 problem per table pg 9/10 to be shown in class

Tuesday 3/29 TAKS warm ups plus chart on top of pg 17, go over S and D from pages 9&10. Made students find mistakes. Explain DR rxns and sol rules, do examples page 16. Did rxn 1 for them, next year do one that has varying charges so kids see that they have to write new formulas. Start pre lab pgs 17-18.

complete pre lab pgs 17-18

Wednesday 3/30 Continued working on DR lab reactions. Pointed out common mistakes. Maybe start with mistakes next year. Ex. CoCl3 + Fe(NO3)3 Co(NO3)3 + Cl2Fe has 4-5 common mistakes kids made.

page 19 and finish lab if needed

Thursday 3/31 Single replacement lab with activity series intro page 12 #2 & 3 parts a &b

Friday 4/1 Nom Quiz 4, finish up Sr and DR labs karma questions

Monday 4/4 warm up – write combustion reactions on page crossword puzzle

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15. Kids had a hard time. Though they should add the O2 to sucrose to make O13. Also thought alcohols did not need to add O2 because they already had O. Next, made activity series from lab. ZnCl2 solution did not react as expected, may need to make new next year. Went over Karma Q.

Tuesday 4/5 test

***This is a tentative schedule and may change as needed. Be flexible!

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“If you don’t make mistakes, you’re not working on hard enough problems. And that’s a big mistake.”-F. Wikzek

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Chemical Equations are the short-hand way of explaining a chemical reaction.

Example of a chemical reaction written in word form:Sulfuric acid decomposes to form sulfur trioxide gas and water.

How to write a chemical equation:First, write the correct formulas for all of the reactants and products.

Sulfuric acid: sulfur trioxide: water:

Next, place the reactants on the left of the arrow and the products on the right. Separate multiple chemicals with + signs.

Then, indicate the state of each chemical using the following abbreviations:

State signifiers after every chemical:(s) solid(l) liquid(aq) aqueous (dissolved in water, called a solution)(g) gas

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According to John Dalton, chemical changes are changes in the groupings of atoms, not changes in the atoms themselves.

Individual chemical changes are called chemical reactions.

In chemical reactions, chemical bonds between atoms are formed and/or broken.

Chemical equations are a short-hand way to represent a chemical reaction.

Signs of a Chemical Change/Reaction

1.

2.

3.

4.

Law of Conservation of Matter

In a chemical reaction, mass is neither created nor destroyed. The form, state, and appearance of matter may

change, but the ___________________ amount of mass stays constant. This law also means that the number of

atoms must stay the same too!

Chemical Reactions and Equations

reactants products

Some VocabularyReactants = starting chemicals Products = ending chemicals

Symbol Explanation of symbol+ separates 2 or more reactants or products “yield”, separates reactants from products

Hint: Acids are ALWAYS (aq)

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Who needs sentences? Chemical Equations tell you everything!

For each of the following sentences, write a correct chemical equation. 1. When you put pieces of calcium metal into hydrochloric acid, it makes dissolved calcium chloride and

flammable hydrogen gas.

2. Solid sodium reacts with water to form sodium hydroxide solution and hydrogen gas.

3. Solid lithium reacts with chlorine gas to produce solid lithium chloride.

4. Crystals of calcium hydroxide react with phosphoric acid to make water and calcium phosphate dissolved in water.

Factors that Affect Reaction Rates

A reaction between two molecules can only occur when the two molecules touch!

1._____________________: Raising the temperature increases the __________at which the molecules move. When molecules move faster, more collisions occur thus making the reaction proceed ______________. The opposite is true for decreasing the temperature.

2.______________________: When the concentration is increased, the number of molecules is increased. When there are more molecules, more collisions occur, which makes the reaction proceed faster. The opposite is true for decreasing the concentration.

3.________________________: When the size of the particles is smaller, the surface area is _____________. This provides access to a greater number of molecules to collide and increases the ________________ of the reaction. The opposite is true for using larger particle sizes.

4._______________________: Even though a catalyst is never used up in a reaction, its presence can ________________ up a reaction by _____________ the energy it takes for the collisions to occur.

NOTE: If heat or a catalyst is used to facilitate a chemical reaction, either a Δ for heat or the formula of the catalyst is written about the reaction arrow.

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Classifying Reactions

FLOWCHART

Yes

Yes

Yes

Yes

Yes

No

No

No

No

Star t Her e!

Questions to Ask:

One Reactant?

One Product?

Oxygen a reactant and water a product?

An element and a compound make a different element and

compound?

Two compounds make two different compounds

Types of Reactions:

Decomposition: A reactant breaks up into pieces.

AX A + X Example: MgO Mg + O2

Synthesis: Reactants combine to make a compound.

A + X AX Example: Mg + O2 MgO

Combustion: Hydrogen or a Hydrocarbon (H and C) burn in Oxygen to

produce water, energy, and often CO2. CjHk + O2 H2O + CO2 Example: H2 + O2 H2O

Single Replacement: An element takes the place of another element in a compound.

A + BX AX + B or BX + Y BY + X Example: Mg + BeO MgO + Be or NaCl + F2 NaF + Cl2

Double Replacement: Elements in two compounds switch places.

AX + BY AY + BX Example: MgO + BeS MgS + BeO

TYPES OF CHEMICAL REACTIONSType Description Form Example

Decomposition Compounds break down AX A + X MgO Mg + O2

Synthesis (combination)

Compounds are formed A + X AX Mg + O2 MgO

Combustion Carbon compounds burning in oxygen, forms water and CO2

CjHk + O2 H2O + CO2 or

CjHkO + O2 H2O + CO2

CH4 + O2 H2O + CO2

CH3OH + O2 H2O + CO2

Single Replacement One element replaces another in a compound

A + BX AX + B or BX + Y BY + X

Mg + BeO MgO + Be or NaCl + F2 NaF + Cl2

Double Replacement Two elements switch places in two compounds

AX + BY AY + BX MgO + BeS MgS + BeO

CH4 + O2 CO2 + H2O

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Practice: Types of Chemical ReactionsHandy Abbreviations: Synthesis: S Decomposition: D Single Replacement: SR

Double Replacement: DR Combustion: C1. A decomposition reaction starts with one reactant and ends up with two or more products. Circle

any decomposition reactions below. If a reaction is NOT a decomposition reaction you should label what type of reaction it is: S, SR, DR, or C.

a. 2NaCl → 2Na + Cl2

b. 2Na + Cl2 → 2NaClc. 2H2O → 2H2 + O2

d. 2H2 + O2 → 2H2Oe. NaOH + HCl → HOH + NaCl

2. A synthesis reaction starts with two reactants and ends up with one product. Circle any synthesis reactions below. If a reaction is NOT a synthesis reaction you should label what type of reaction it is: D, SR, DR, or C.


b. 2Na + HCl → H2 + 2NaClc. 2H2 + O2 → 2H2Od. NaOH + HCl → HOH + NaCle. 2K + Cl2 → 2KCl

3. A single replacement reaction starts with two reactants and ends up with two products. The uncombined element takes the place of the combined element in the compound. Circle any single replacement reactions below. If a reaction is NOT a single replacement reaction you should label what type of reaction it is: S, D, DR, or C.


b. NaOH + HCl → HOH + NaClc. K + AgCl → Ag + KCld. Ca + S → CaSe. 2Na + HCl → H2 + 2NaCl

4. A double replacement reaction starts with two reactants and ends up with two products. In this case both reactants are compounds and both products are compounds. They simply change partners. Circle any double replacement reactions below. If a reaction is NOT a double replacement reaction you should label what type of reaction it is: S, D, SR, or C.


b. NaOH + HCl → HOH + NaClc. 2Na + HCl → H2 + 2NaCld. KOH + HNO3 → HOH + KNO3

e. Ca + S → CaS

5. A combustion reaction starts with two reactants and ends up with two products. One reactant is always oxygen (O2) and the products are always water (H2O) and carbon dioxide (CO2). Circle any combustion reactions below. If a reaction is NOT a combustion reaction you should label what type of reaction it is: S, D, SR, DR, or none of these.

a. C3H5(NO3)3 → CO2 + H2O + O2 +N2

b. C6H12O6 + O2 → CO2 + H2O c. Fe + O2 → Fe2O3

d. CH4 + O2 → CO2 + H2Oe. FeS2 + O2 → Fe2O3 + SO2

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Suggested order of balancing

M=metals I=ions (polyatomic) N=nonmetals H=Hydrogen O=Oxygen

WHY MUST CHEMICAL EQUATIONS BE BALANCED?In a chemical reaction, the mass of the products must be equal to the mass of the reactants.We cannot lose or gain any mass during the reaction. We must follow the law of conservation of mass.

Law of Conservation of Matter – matter is neither created nor destroyed. The form of matter may change (ex: liquid changes into gas), but the TOTAL amount of matter (mass) stays constant. Assume you have 1 mole of each of the chemicals in the reactants and products below:

N2 + H2 NH3

Mass of Reactants Mass of Products

N2NH3

H2

Total mass Total mass

Are the masses equal? Is the equation balanced?

How to Balance Equations Using Number of Atoms (rather than molar mass)1. Count the number of atoms of each element in the reactants and products.2. Balance the elements ONE AT A TIME. Do this by using only coefficients (the big numbers that we

put in front of an element/compound). You may NOT CHANGE THE SUBSCRIPTS in the chemical formula of a substance.

3. A helpful order for choosing which elements to balance first: MINHO!4. Check your balanced equation. Make sure all coefficients are in the

lowest possible ratio.

To confirm that the Law of Conservation of Mass has been followed, check the masses:

___N2 + ___H2 ___NH3

Mass of Reactants Mass of Products

___*N2 ___*NH3

___*H2

Total mass Total mass

Are the masses equal? Is the equation balanced?

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Balancing Equations

8

____ N2 + ____ H2 ____ NH3

Reactants side Elements Products side

N

H

Practice Balancing Equations:

1) ____ KClO3 ____ KCl + ____ O2

2) ____ NaCl + ____ F2 ____ NaF + ____ Cl2

3) _____N2O5 + _____H2O _____HNO3

4) ____ AlBr3 + ____ K2SO4 ____ KBr + ____ Al2(SO4)3

5) ____ HNO3 + ____ NaHCO3 ____ NaNO3 + ____ H2O + ____ CO2

6) ____ Pb(OH)2 + ____ HCl ____ H2O + ____ PbCl2

7) _____CaCl2 + _____Na3PO4 _____NaCl + _____Ca3(PO4)2

Ca

Cl

Na

PO4

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Wanna know a secret? If a polyatomic ion is present in both the reactants and products without getting broken up in the reaction, you can list it like an element in your atom count.

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BALANCING AND IDENTIFYING CHEMICAL EQUATIONS at the same time!

Balance the following chemical equations and identify the reaction type:C = Combustion; D = Decomp.; S = Synthesis; SR = Single Replacement; DR = Double Replacement

1. _____K3PO4 + _____HCl _____KCl + _____H3PO4 Rxn Type:_______

2. _____H2O2 _____H2O + _____O2 Rxn Type:_______

3. _____Na + _____H2O _____NaOH + _____H2 Rxn Type:_______

4. _____Mg(NO3)2 + _____K3PO4 _____Mg3(PO4)2 + _____KNO3 Rxn Type:_______

5. _____C3H8 + _____O2 _____CO2 + _____H2O Rxn Type:_______

6. _____C8H18 + _____O2 _____CO2 + _____H2O Rxn Type:_______

7. _____P + _____O2 _____P2O5 Rxn Type:_______

8. _____Ag2O _____Ag + _____O2 Rxn Type:_______

9. _____K + _____MgBr2 _____KBr + _____Mg Rxn Type:_______

10. _____S8 + _____F2 _____SF6 Rxn Type:_______

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Writing and Balancing Equations for Synthesis and Decomposition Reactions1. Solid silver reacts with iodine gas to produce solid silver iodide.

a. Write a chemical equation for this reaction with correct chemical formulas. (silver’s oxidation state is always 1+)

b. Rewrite and balance the equation.

c. Identify the type of reaction ___________________________

2. Solid sodium chlorate breaks down into solid sodium chloride and oxygen gas when heated.a. Write a chemical equation for this reaction with correct chemical formulas.



3. When exposed to air, solid chromium reacts with oxygen gas to form solid chromium (III) oxide.a. Write a chemical equation for this reaction with correct chemical formulas.



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4. Fuel cells work by combining hydrogen gas and oxygen gas to form water vapor in an exothermic reaction.a. Write a chemical equation for this reaction with correct chemical formulas.



5. When heated, solid sodium bicarbonate forms solid sodium carbonate, water vapor, and carbon dioxide gas.a. Write a chemical equation for this reaction with correct chemical formulas.



6. Nitrogen gas reacts with oxygen gas to produce nitrogen dioxide gas.a. Write a chemical equation for this reaction with correct chemical formulas.



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Single Replacement Reactions are reactions that involve an element replacing one part of a compound. The products include the displaced element and a new compound.

An element can only replace another element that is less active than itself. Metals can only replace metals. Nonmetals can only replace nonmetals.

METALS:A more active metal replaces a less active metal in a compound.

example Silver nitrate is added to a sample of zinc metal.2AgNO3 (aq) + Zn (s) Zn(NO3)2 (aq) + 2Ag (s)

How will you know which metals are more active than other metals? We will test them in a Single Replacement Lab and find out! After the lab, we will fill in the official series below.

General activity series for METALS

more active less active

NONMETALS:A more active nonmetal replaces a less active nonmetal in a compound.

example Chlorine gas is bubbled into a solution of potassium iodide.Cl2 (g) + 2KI (aq) I2 (l) + 2KCl (aq)

General activity series for NONMETALS

more active less active

Single Replacement Practice Correct formulas must be written for each compound before an equation may be balanced!

1. An aluminum strip is immersed in a solution of silver nitrate. (silver’s oxidation state is always 1+)a. Write a chemical equation for this scenario with correct chemical formulas and state signifiers.


c. Will a reaction occur?___________________________

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2. Fluorine gas is bubbled into a solution of aluminum chloride.a. Write a chemical equation for this scenario with correct chemical formulas and state signifiers.



3. Magnesium turnings are added to a solution of lead (II) acetate.a. Write a chemical equation for this scenario with correct chemical formulas and state signifiers.



4. A solution of iron (III) chloride is poured over a piece of platinum wire. (Platinum’s common oxidation state is 2+)

a. Write a chemical equation for this scenario with correct chemical formulas and state signifiers.



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Single Replacement Reaction Lab Safety and clean up will be considered part of the grade. Have your lab stamped when your station is clean. Minus 10 points every time someone in your group removes their goggles.

Some important info:Zinc’s oxidation state is +2 Copper’s oxidation state is +2 Tin’s oxidation state is +2

PRE-LAB1. In the table below, write down the metals and solutions (from your lab table) you will be using.

LAB2. Set up the transparency like this:

a. Put 1 piece of each metal across each ROW. (5 rows total)b. Put 1-3 drops of solution on top of each metal in a COLUMN. c. Look for changes as soon as you add solution, but some take longer.

3. Record your results in the data table below. What happened in each combination? Remember to look for subtle changes as well as drastic changes, but only record chemical changes.

DATA TABLE

CLEAN-UP4. Re-capture any pieces of metal, rinse them with water, and place them on a paper towel to dry. You

may need to clean them with a brush if they do not rinse clean.5. Rinse the transparency in the sink and dry it gently with a paper towel. Have your station’s cleanliness

checked and signed. (10 points)

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MetalsSolutions

STAMP

15

Metal Solution

POST-LAB6. For each reaction you observed, write a balanced chemical equation.

7. Which metals started in solution and came out as solids in the reaction (like Jennifer Aniston)?

(these are less reactive)

8. Which metals started as solids and ended up in dissolved compounds (like Angelina Jolie)?

(these are more reactive)

9. Some metals are more reactive than others. Create an activity series for the metals you observed. Using your data, place the METALS in order from most reactive to least reactive:

Observed activity series for METALS

10. Alkali metals are very reactive and never found in nature in their pure form. Predict the outcome of the following combination and explain your answer using what you learned in this lab:

NaCl(aq) + Zn(s)

11. Make a “general rule” type of statement about the circumstances under which ‘no reaction’ will occur? Do not mention any chemicals by name.

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Most reactive: :Least reactive

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Combustion Reactions occur when hydrocarbons or carbohydrates “burn” in oxygen. The products are ALWAYS water and carbon dioxide.

Generic unbalanced equation: C#H# + O2 CO2 + H2O

Example: Ethanol (C2H5OH) combusts. Write and balance the equation.

Practice! Write balanced combustion reactions for:1. C8H18 (octane)

2. C12H22O11 (sucrose)

3. CH3OH (methanol)

4. C3H7OH (propanol)

5. C4H10 (butane)

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CAUTION:Combustion reactions are

HARD to BALANCE!Count all the oxygens, every time you make a

change!

17

ION

Double Replacement Reactions are reactions that involve two compounds swapping cations and anions with each other. These reactions only occur when one of the products is insoluble (will not stay dissolved in water). Why is this?

When an ionic compound is dissolved in water, the ions completely separate (dissociate) from each other. It’s like ion soup! When two solutions are mixed together, they remain ion soup unless something solid, liquid or gas is formed to take it out of the soup. Use solubility rules for reference to determine whether the products are insoluble or soluble.

CaCl2 (aq) + Na2CO3 (aq) CaCO3 (s) + 2NaCl (aq)

Solubility Rules (use as a reference to determine whether or not double replacement reactions happen)

Soluble (aq) = will dissolve in water, aqueous Insoluble (s) = will not dissolve in water, stay solid. Called a precipitate when formed in a reaction.

Ex.1 _____AlBr3 + _____K2SO4 _____Al2(SO4)3 ( ) + _____KBr( ) Rxn occur?:_______Ex. 2_____KI + _____Pb(NO3)2 _____KNO3( ) + _____PbI2( ) Rxn occur?:_______Ex. 3_____AgNO3 + _____K2SO4 _____KNO3( )+ _____Ag2SO4( ) Rxn occur?:_______Ex. 4_____FeCl3 + _____Na2CO3 _____Fe2(CO3)3( )+ _____NaCl( ) Rxn occur?:_______Ex. 5_____FeCl3 + _____NaOH _____Fe(OH)3( )+_____NaCl( ) Rxn occur?:_______Ex. 6_____HCl + _____Ca(OH)2 _____CaCl2( ) + _____H2O( ) Rxn occur?:_______

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(aq)

(aq)(s)

(s)

and Ag+

18

Double Replacement LabObjective: You will use the solubility rules to create 5 solid precipitates using double replacement reactions.

Task 1: Write correct chemical formulas for the ionic compounds you can use.Name of chemical in

solutionChemical formula

Nickel (II) nitrate

Iron (III) nitrate

Silver nitrate

Sodium phosphate

Sodium hydroxide

Sodium sulfide

Sodium chloride

Cobalt (II) chloride

Potassium chromate

Task 2: Pick 5 different combinations of the compounds above that will result in double replacement reactions with a solid product. Write the formula for the solid product in the correctly labeled blank.

Reaction #1

______________(aq) + ______________(aq) ______________(s) + ______________(aq) This reaction has: Checked by teachercorrect state indicatorscorrect chemical formulasbalanced equation

Reaction #2


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Teacher has checked these formulas are correct:

X____________________

Silver’s oxidation state is always +1

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Reaction #3


Reaction #4


Reaction #5


Task 3: Once you have 5 correct double replacement reactions above, go to the lab area and perform each reaction to observe the formation of your predicted product.

Use a glass wellplate as the reaction surface. Use only 1 drop of each reactant. Combine only the chemicals you predicted in the reactions above. (no unauthorized experiments) Describe the appearance of the precipitate in each reaction. Write your description in the space

below the formula for the precipitate in the chemical reaction. Clean the glass wellplate thoroughly when you have done all 5 reactions.

Task 4: In your own words, describe a precipitate and explain how it forms. (Answer both parts)

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Double Replacement PracticeUse solubility rules determine whether or not a reaction will occur. If all products are soluble (aqueous), no reaction occurred; write “NR” in the blank. Correct formulas must be written for each compound before an equation may be balanced!

1. Silver nitrate and potassium chromate (silver’s oxidation state is always 1+)a. Write a chemical equation for this reaction with correct chemical formulas and state signifiers.


c. Will a reaction occur? ___________________________

2. Ammonium chloride and cobalt(II) sulfatea. Write a chemical equation for this reaction with correct chemical formulas and state signifiers.



3. Lithium hydroxide and sodium chromatea. Write a chemical equation for this reaction with correct chemical formulas and state signifiers.



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ION

4. Zinc acetate and cesium hydroxide (zinc’s oxidation state is always 2+)a. Write a chemical equation for this reaction with correct chemical formulas and state signifiers.


c. Will a reaction occur? ___________________________5. Ammonium sulfide and lead (II) nitrate

a. Write a chemical equation for this reaction with correct chemical formulas and state signifiers.



6. Iron (III) sulfate and barium iodidea. Write a chemical equation for this reaction with correct chemical formulas and state signifiers.



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Name: ____________________________________ Period:chemcast.weebly.com/.../chemical_reactions_packet_w_dr_lab.docx · Web viewwarm up nomenclature + sol rules. Gave packet. Did page