AP Chemistry
Summer
Prerequisite Review
ANSWER KEY
Visit us at chemistrywithrourke.weebly.com
Adapted from: Bergmann-Sams
DUE JULY 1
PART A. COMPOUNDS AND EQUATIONS
Balancing Ionic Compounds
Given the names of the elements that form a compound, determine their ionic charge and write the
chemical symbols for the compound.
EX: Lithium Oxygen
Li2O Li+ O21. Sodium Sulfur
Na+ S2Na2S
2. Potassium Chlorine
K+ ClKCl
7. Ammonium Phosphate
NH4+ PO43(NH4)PO4
8. Hydronium Bromine
H3O+ BrH3OBr
3. Rubidium Sulfate
Rb+ SO42Rb2SO4
9. Cupric Carbonate
Cu2+ CO32CuCO3
4. Magnesium Nitrite
Mg2+ NO2Mg(NO2)2
10. Iron (II) Iodate
Fe2+ IO3Fe(IO3)2
5. Strontium Iodine
Sr2+ ISrI2
11. Ferrous hydroxide
Fe2+ OHFe(OH)2
6. Aluminum Perchlorate
Al3+ ClO4Al(ClO4)3
12. Ferric Nitrate
Fe3+ NO3Fe(NO3)3
Given chemical symbols below, determine the ionic charges of each element and then write the balanced
chemical symbol for each compound formed.
EX: Na ClO3 Na2CO3
5. Ca N
2+
1. H Pb
Ca3N2
H2Pb
6. Cs Br
2. Li NO3
CsBr
LiNO3
3. Be CO3
BeCO3
4. H SO3
H2SO3
7. Fe3+ F
FeF3
8. Ag+ Se
Ag2Se
Naming Ionic Compounds
For each ionic compound, list the cation(s), anion(s), chemical formula, and electron dot structure
Chemical Formula
1. sodium iodide
cations
_____Na_______
anions
_____I________
Electron Dot Structure
NaI
2. magnesium chloride
cations
anions
Electron Dot Structure
____Mg2+_______
MgCl2
-
____Cl ________
3. aluminum sulfide
cations
____Al3+________
anions
_____S2-______
Chemical Formula
cations
_____Fe3+_______
anions
______O2-______
5. stannous bromide
Electron Dot Structure
Al2S3
Chemical Formula
4. iron (III) oxide
cations
Chemical Formula
Electron Dot Structure
Fe2O3
Chemical Formula
Electron Dot Structure
_____Sn2+_________
SnBr2
anions
-
_____Br _______
6. plumbic oxide
cations
____Pb2+________
anions
____O2- ____
Chemical Formula
PbO
Electron Dot Structure
Balance Chemical Reactions
Rewrite each chemical equation with the correct coefficients necessary to balance the equation.
1. NaCO3(aq) + Ca(OH) (aq)  _____ NaOH(aq) + _____ CaCO3(s)
Na2CO3(aq) + Ca(OH)2 (aq)  ___2_ NaOH(aq) + _____ CaCO3(s)
2. KPO4(aq) + _____ MgCl(aq)  _____ Mg(PO4) (s) + _____ KCl (aq)
2 K3PO4(aq) + ___3_ MgCl2(aq)  _____ Mg3(PO4)2 (s) + ___6_ KCl (aq)
3. Cu (s) + ____ H2SO4 (aq)  ____ CuSO4 (aq) + ____ H2O (l) + ____ SO2 (g)
Cu (s) + __2__ H2SO4 (aq)  ____ CuSO4 (aq) + ___2_ H2O (l) + ____ SO2 (g)
4. FeS (s) + HCl (aq)  FeCl (aq) + HS (g)
FeS (s) + 2 HCl (aq)  FeCl2(aq) + H2S (g)
5. Fe (s) + CuNO3 (aq)  Cu (s) + Fe(NO3) (aq)
Fe (s) + 2 CuNO3 (aq)  2 Cu (s) + Fe(NO3)2 (aq)
6. KI (aq) + Cl2 (g)  KCl (aq) +I2 (aq)
2KI (aq) + Cl2 (g)  2 KCl (aq) + I2 (aq)
7. Al (s) + S (s)  AlS (s)
2Al (s) + 3 S (s)  Al2S3(s)
-4-
Reaction Types
This is an instructional sheet to help you understand chemical reactions and to be able to predict the
products of chemical reactions.
There are 5 types of reactions in chemistry.
I.
Combustion
a. The combustion of an organic material
i. EX: C3H8 + 5O2  3CO2 + 4H2O
ii. The products are always carbon dioxide and water. The only thing that changes is the
organic material and the coefficients needed to balance the equation.
II.
Combination
a. A + B  X
b. EX: 2Mg + O2  2MgO
III.
Single-Replacement
a. Use the Activity Series to determine if an elemental metal will replace the metal in a compound
based upon the reactivity of the metals
i. EX: Fe + 2AgNO3  Fe(NO3)2 + 2Ag
ii. EX: Cu + Zn(NO3)2  X or NR
IV.
Double-Replacement
a. The cations of two ionic compounds exchange anionic partners
i. EX: NaOH + HCl  NaCl + HOH
V.
Decomposition
a. The opposite of a combination reaction
b. A compound decomposes into elements and compounds
c. Typical products include CO2, H2, O2
i. EX: BaCO3  BaO + CO2
ii. 2Zn(OH)2  2ZnO + 2H2
iii. Ni(ClO4)2  NiCl2 + 8O2
d. There are tests for each type of product formed
Predict the products. Identify the reaction type.
ALWAYS balance the equation.
1. Zn2+ + Ca(OH)2  Ca + Zn(OH)2
Single replacement
2. LiCl + KBrO3  LiBrO3 + KCl
Double replacement
3. 2C2H6 + 7O2  4CO2 + 6H2O
combustion
4. 2 MgO + Δ  2 Mg + O2
decomposition
5. 2 Hydrogen + Oxygen  2H2O
combination
-5-
Balance and Identify Chemical Reactions
Balance each equation with coefficients (all componds should already be balanced) and identify the reaction
type.
1. 2Hf + 2N2  Hf2N4
combination
2. Mg + H2SO4  MgSO4 + H2
Single replacement
3. 2C2H6 + 7O2  4CO2 + 6H2O
combustion
4. Pb(NO3)2 + 2 NaI  PbI2 + 2 NaNO3
Double replacement
5. 3Fe + 2O2  Fe3O4
combination
6. 2Pb(NO3)2  2PbO + 4NO2 + O2
decomposition
7. Hg(NO3)2 + 2NH4SCN  Hg(SCN)2 + 2NH4NO3
Double replacement
8. (NH4)2SO4 + 2NaOH  2NH3 + 2H2O + Na2SO4
Decomposition or Double Replacement
Predict the products, balance, and identify the type of reaction
9. Al + H2SO4  H2 + Al2(SO4)3
Single replacement
10. 2HCl + Ba(OH)2  2H2O + BaCl2
Double replacement
11. 2Au + 2HCl  2AuCl + H2
Single Replacement
-6-
Decomposition and Synthesis Reactions
A synthesis reaction is the opposite of a decomposition reaction. This practice will help us recognize the
products for common decomposition reactions
1) Sodium + Oxygen
4Na + O2  2Na2O
2) Lithium + Sodium chloride
Li + NaCl  LiCl + Na
3) Sodium chloride and heat
NaCl + heat  Na + Cl2
4) Potassium chlorate
2KClO3 + heat  2KCl + 3O2
5) Copper (II) + Oxygen
2Cu + O2  2CuO
6) Aluminum + Hydrogen chloride
2Al + 6HCl  3H2 + 2AlCl3
7) Magnesium + Oxygen
2Mg + O2  2MgO
8) Silver + Chlorine
2Ag + Cl2  2AgCl
9) Aluminum oxide and heat
2Al2O3 + heat  4Al + 3O2
-7-
DUE AUGUST 1
PART B. STOICHIOMETRY
Stoichiometry Worksheet: Molecule to Mass/Mole
1. How many molecules are there in 24 grams of FeF3?
1.28x1023 molecules FeF3
2. How many molecules are there in 450 grams of Na2SO4?
1.91x1024 molecules Na2SO4
3. How many grams are there in 2.3 x 1024 atoms of silver?
411.9 g Ag
4. How many grams are there in 7.4 x 1023 molecules of AgNO3?
208.8 g AgNO3
5. How many grams are there in 7.5 x 1023 molecules of H2SO4?
122.1 g H2SO4
6. How many molecules are there in 122 grams of Cu(NO3)2?
3.92x1023 molecules Cu(NO3)2
7. How many grams are there in 9.4 x 1025 molecules of H2?
312.3 g H2
8. How many molecules are there in 230 grams of CoCl2?
1.06x1024 CoCl2
-8-
Stoichiometry Worksheet: Moles and Moles
1. Carbon disulfide is an important industrial solvent. It is prepared by the reaction of coke with sulfur
dioxide:
5C(s) +
2SO2(g) -----> CS2(s)
+
4CO(g)
a. How many moles of CS2 form when 6.3 mol of C reacts? THIS EXAMPLE IS DONE FOR
YOU!
6.3mol C 1 mol CS2 = 1.26 mol CS2
5 mol C
2.
How many moles of carbon are needed to react with 7.24 moles of SO2
18.1 mol C
3. Silver can be made according to the following equation:
2AgNO3+ Ca  Ca(NO3)2 + 2Ag
a. Balance the equation
b. Identify the type of reaction Single Replacement
c. If 35.3 moles of silver nitrate are reacted how many moles of silver are produced?
35.3 mol Ag
4. How many moles of carbon dioxide are formed when 44-mol of CH4 is burned?
44 mol CO2
5. How many moles of calcium phosphate is formed when 32.5-mols of calcium nitrate reacts with sodium
phosphate?
3Ca(NO3 )2 + 2Na3PO4 ® Ca3 (PO4 )2 + 6NaNO3
32.5mol
?mol
32.5molCa(NO3 )2 1molCa3 (PO4 )2
x
= 10.8molCa3 (PO4 )2
1
3molCa(NO3 )2
-9-
Stoichiometry Worksheet: Moles and Moles
6. Car batteries are called lead storage batteries because of their use of large quantities of lead. These
batteries utilize the following equation.
Pb + PbO2 +2H+ + 2HSO4-  2PbSO4 + 2 H2O
34.3gPbO2 1molPbO2 2molH 2O 18gH 2O
x
x
x
=
1
239gPbO2 1molPbO2 1molH 2O
5.16gH 2O
34.3gPbO2 1molPbO2 2molPbSO4 303gPbSO4
x
x
x
=
1
239gPbO2 1molPbO2 1molPbSO4
= 87.0gPbSO4
7. 32.5-g of ZnSO4 reacts to form how many grams of BaSO4 according to the following equation.
a. Balance the equation
b. Identify the type of reaction
32.5gZnSO4 1molZnSO4 1molBaSO4 233gBaSO4
x
x
x
=
1
161gZnSO4 1molZnSO4 1molBaSO4
= 47.0gBaSO4
8. When sodium metal is added to water the resulting gas, Hydrogen can often explode. How many Liters
of hydrogen gas is produced when 41.2-g of sodium is dropped into water. You must balance the
equation in order to solve the problem.
Na + HOH  NaOH + H2
41.2gNa 1molNa 1molH 2 22.4LH 2
x
x
x
=
1
23gNa 2molNa 1molH 2
= 20.1LH 2
9. 43.5-grams of barium sulfate is formed from the reaction of barium nitrate and sodium sulfate. How
many moles of sodium sulfate reacted?
Ba(NO3 )2 + Na2 SO4 ® BaSO4 + 2NaNO3
?mol
43.5g
43.5gBaSO4 1molBaSO4 1molNa2 SO4
x
x
= 0.187molNa2 SO4
1
233gBaSO4 1molBaSO4
- 10 -
Stoichiometry Worksheet: Volume
1. Barium oxide reacts with carbon dioxide to make Barium carbonate:
BaO + CO2  BaCO3
a. Balance the equation
b. Identify the type of reaction Single Replacement
c. If 23.4 moles of barium oxide react, how many liters of CO2 are required at STP?
23.4molBaO 1molCO2 22.4LCO2
x
x
= 524LCO2
1
1molBaO 1molCO2
2. Ammonia, (NH3) is produced by reacting its elements with each other according to the following
equation:
N2 + 3H2  2NH3
a. Balance the equation
b. Identify the type of reaction Combination
c. If 34.3-L of nitrogen is reacted with hydrogen, how many liters at STP of ammonia will be
formed?
34.3LN 2 2LNH 3
x
= 68.6LNH 3
1
molN 2
3. Calculate the volume of carbon dioxide produced when 250 g of pentane, C5H12, burn. Assume the
carbon dioxide is cooled to STP.
250gC5 H12 1molC5 H12 5molCO2 22.4LCO2
x
x
x
=
1
72gC5 H12 1molC5 H12 1molCO2
389LCO2
4. Propane is a gas used often for backyard grills. How many Liters of CO2 is produced when 54.9-L of
propane (C3H8) is burned according to the following equation. Again, you must balance the equation in
order to solve the problem.
C3H8 + O2  CO2 + H2O
54.9LC3 H 8
3LCO2
x
= 165LCO2
1
1molC3 H 8
- 11 -
Stoichiometry Worksheet: Grams
1. 14.5-g of cesium explosively reacts with water to form hydrogen and cesium hydroxide. How many
molecules of hydrogen were formed?
2Cs  2 H 2O  2CsOH  H 2
14.5 g
?molec
14.5gCs 1molCs 1molH 2 6.02 x1023 molecH 2
x
x
x

1
133gCs 2molCs
1molH 2
3.28 x1022 molecH 2
2. How many molecules of chlorine are needed to react with 5.6 g of iron to form iron III chloride?
5.6gFe 1molFe 3molCl2 6.02 x10 23 molecCl2
x
x
x
=
1
56gFe 2molFe
1molCl2
9.03x10 22 molecCl2
3. What mass of ammonia, NH3, is necessary to react with 2.1 x 1024 molecules of oxygen when ammonia
(NH3) reacts with oxygen to form water and nitrogen dioxide?
2.1x10 24 molecO2
1molO2
4molNH 3 17gNH 3
x
x
x
=
1
6.02x10 23 molecO2 7molO2 1molNH 3
33.9gNH 3
4. 22.8-g of NaOH is reacted with hydrochloric acid. How many grams of water is formed?
5. 32.5-grams of iron III chloride reacts with silver nitrate. How many grams of silver chloride are
formed?
3.25gCu(NO3 ) 2 1molCu(NO3 ) 2 1molCu(OH) 2 97.5gCu(OH) 2
x
x
x
=
1
187.5gCu(NO3 ) 2 1molCu(NO3 ) 2 1molCu(OH) 2
1.69gCu(OH) 2
- 12 -
Stoichiometry Worksheet: Grams
6. 34.5-grams of Lithium reacts with Chromium III chloride. How many grams of lithium chloride is
formed?
3Li + CrCl3 ® 3LiCl + Cr
34.5g
?g
34.5gLi 1molLi 3molLiCl 42.5gLiCl
x
x
x
= 209gLiCl
1
7gLi
3molLi 1molLiCl
7. 43.5-grams of copper II sulfate is reacted with barium nitrate. How many grams of precipitate are
formed?
8. Calculate the mass of silver needed to react with chlorine to produce 84 g of silver chloride.
CuSO4  Ba ( NO3 ) 2  BaSO4 ( s )  Cu( NO3 ) 2 ( aq)
43.5 g
g?
43.5gCuSO4 1molCuSO4 1molBaSO 4 233 gBaSO4
x
x
x

1
159.5 gCuSO4 1molCuSO4 1molBaSO4
63.5 gBaSO4
9. Silver nitrate reacts with sodium chloride to make the silver chloride and sodium nitrate. When 2.53
grams of silver nitrate is reacted. How many grams of silver chloride are formed?
2.53gAgNO3 1molAgNO3 1molAgCl 143.5gAgCl
x
x
x
=
1
170gAgNO3 1molAgNO3 1molAgCl
2.14gAgCl
10. When 3.25 g of copper II nitrate reacts with ammonium hydroxide. How many grams of the precipitate
will form?
3.25gCu(NO3 )2 1molCu(NO3 )2 1molCu(OH )2 97.5gCu(OH )2
x
x
x
=
1
187.5gCu(NO3 )2 1molCu(NO3 )2 1molCu(OH )2
1.69gCu(OH )2
- 13 -
Stoichiometry Worksheet: Limiting Reactants
1. When 114.0 g of iron and 292.7 g of chlorine gas reacts, iron(III) chloride is formed.
2 Fe  3Cl 2  2 FeCl3
114g 292.7g
?g
114gFe 1molFe 2molFeCl3 162.5 gFeCl3
x
x
x
 331gFeCl3
1
56 gFe
2molFe
1molFeCl3
292.7gCl 2 1molCl 2 2molFeCl3 162.5 gFeCl3
x
x
x
 447 gFeCl3
1
71gCl 2
3molCl 2
1molFeCl3
Fe is the LR because it yielded the smallest answer
114gFe 1molFe 3molCl 2 71gCl 2
x
x
x
 217 gCl 2 used up
1
56 gFe 2molFe 1molCl 2
292.7  217 g  75.9 gCl 2 left
2. 20 L of oxygen react with 1.0L of methyl alcohol, CH3OH.
2CH 3OH + 3O2 ® 2CO2 + 4H2 O
1.0L
20L
?L
1.0 LCH3 OH
4LH 2 O
x
= 2LH2 O
1
2LCH3 OH
20LO2 4LH2 O
x
= 27LH 2 O
1
3LO2
CH 3OH is the LR because it yielded the smallest answer
1.0 LCH3 OH
3LO2
x
= 1.5LO2
1
2LCH3 OH
20L - 1.5L = 18.5LO2 Left
- 14 -
Stoichiometry Worksheet: Limiting Reactants
3. 25 g of hydrazine, N2H4(l), and 66 g of hydrogen peroxide, H2O2(l), react to produce nitrogen gas and water.
N2 H4 + 2H2 O2 ® N2 + 4H2 O
25g
66g
g?
25gN2 H4 1molN2 H4 1molN 2
28gN2
x
x
x
= 22gN 2
1
32gN2 H4 1molN2 H4 1molN 2
66gH2 O2 1molH2 O2
1molN2
28gN2
x
x
x
= 27gN2
1
34gH 2O2 2molH2 O2 1molN2
N2 H4 is the LR because it yielded the smallest answer
25gN2 H4 1molN2 H4 2molH2 O2 34gH 2 O2
x
x
x
= 53gH2 O2
1
32gN2 H4 1molN2 H4 1molH2 O2
66g - 53g = 13gH2 O2 leftover
4. 22.5 grams of lithium reacts with 33.5 grams of aqueous aluminum sulfate. This is a single replacement
reaction.
6Li + Al2 (SO4 )3 ® 3Li2 SO4 + 2Al
22.5g
33.5
g?
22.5gLi 1molLi 3molLi2 SO4 110 gLi2 SO4
x
x
x
= 177gLi2 SO4
1
7g
6molLi
1molLi2 SO4
33.5gAl2 (SO4 ) 3 1molAl2 (SO4 )3
3molLi2 SO4
110gLi2 SO4
x
x
x
= 32gLi2 SO4
1
342gAl2 (SO4 )3 1molAl2 (SO4 )3 1molLi2 SO4
Al2 (SO4 ) 3 is the LR since it yields the smaller value
33.5gAl2 (SO4 ) 3 1molAl2 (SO4 )3
6molLi
7gLi
x
x
x
= 4.1gLi
1
342gAl2 (SO4 )3 1molAl2 (SO4 )3 1molLi
22g - 4.1g = 18gLiLeftover
- 15 -
Stoichiometry Worksheet: Percent Yield
1. 15.5-g of NH4Cl reacts with an excess of AgNO3. In the reaction 35.5-g AgCl is produced. NH4NO3 is the
other product. What is the percent yield?
15.5gNH 4 Cl 1molNH 4 Cl 1molAgCl 143.5gAgCl
x
x
x
=
1
53.5gNH 4 Cl 1molNH 4 Cl 1molAgCl
41.57gAgCl
%=
35.5g
x100 = 85.3%
41.57g
2. Potassium Chlorate decomposes according to the following reaction.
2KClO3  2KCl +3 O2
a. In an experiment 32.5-g of KClO3 is decomposed and 15.2-g of KCl is formed. What is the percent
yield?
32.5gKClO3 1molKClO3
2molKCl 74.5gKCl
x
x
x
=
1
122.5gKClO3 2molKClO3 1molKCl
= 19.7gKCl
%=
15.2g
x100 = 76.9%
19.7g
3. Nitrogen gas reacts with hydrogen gas to make ammonia (NH3). 15.5-L of N2 reacts at STP to make 30-L of
ammonia. What is the percent yield?
15.5LN 2 2 LNH 3
x
 31LNH 3
1
1LN 2
%
30 L
x100  97%
31L
4 What is the percent yield of oxygen gas if 54L of O2 can be obtained from the thermal decomposition of
500.0 g of potassium chlorate?
KClO3  KCl + O2
- 16 -
Stoichiometry Worksheet: Mixed Problems
1. How many grams of water are formed when 12.5-g of hydrogen reacts with oxygen?
12.5gH 2 1molH 2 2molH 2O 18gH 2O
x
x
x
=
1
2gH 2
2molH 2 1molH 2O
= 112.5gH 2O
2. How many liters of carbon dioxide are formed when 12.3-g of sodium carbonate reacts with 2.0-L of
hydrogen chloride. The reaction is printed below:
Na2CO3 + HCl  NaCl + H2O + CO2
12.3gNa2CO3 1molNa2CO3
1molCO2
22.4LCO2
x
x
x
=
1
106Na2CO3 1molNa2CO3 1molCO2
= 2.60LCO2
2.0LHCl 1LCO2
x
= 1.0LCO2
1
2LHCl
= 1.0LCO2 : Answer because it is the lowest
3.
How many grams of precipitate are formed when 24.3-g of zinc nitrate reacts with 20.5-g of sodium
phosphate?
24.3gZn(NO3 )2 1molZn(NO3 )2 1molZn3 (PO4 )2 385gZn3 (PO4 )2
x
x
x
=
1
189gZn(NO3 )2 3molZn(NO3 )2 1molZn3 (PO4 )2
= 16.5gZn3 (PO4 )2 :: This is the answer b/c it is lowest
20.5gNa3PO4 1molNa3PO4 2molNa3PO4 385gZn3 (PO4 )2
x
x
x
=
1
164gNa3 PO4 3molZn(NO3 )2 1molZn3 (PO4 )2
= 32.1gZn3 (PO4 )2
4. How many liters of oxygen are produced when 3.25-g of KClO3 decomposes into KCl and O2?
3.25gKClO3 1molKClO3
3molO2
22.4LO2
x
x
x
=
1
122.5gKClO3 2molKClO3 1molO2
= 0.89LO2
- 17 -