UNIT 8
CHEMICAL REACTIONS
Practice Test
NAME _____________________________
A) Balance the following equations by writing coefficients where needed
AND
B) Classify each reaction as synthesis, decomposition, replacement, double
displacement or combustion by writing the classification (don’t abbreviate) in the
space provided:
1)
2 N2 + 3 H2 
2 NH3
CLASSIFICATION: __synthesis_________________
2)
3 HNO3 + Al(OH)3  Al(NO3)3 + 3 H2O
CLASSIFICATION: ____double replacement_______
3)
2 K + 2 H2O  H2 + 2 KOH
CLASSIFICATION: __single replacement______
4)
Ni + 2 CuCl  NiCl2 + 2 Cu
CLASSIFICATION: __single replacement____
C) Write the following as balanced reaction equations
AND
D) Use symbols to represent as much information as possible (ex: heat, gas,
precipitate,...)
1) Solid sodium bicarbonate reacts with aqueous hydrochloric acid (HCl) to form sodium
chloride solution, water, and carbon dioxide gas.
NaHCO3(s) + HCl(aq) → NaCl(aq) + H2O(l) + CO2(g)
2) Solid copper reacts with aqueous silver nitrate to form copper(II) nitrate solution and
silver.
Cu(s) + 2 AgNO3(aq) → Cu(NO3)2(aq) + 2 Ag(s)
3) Chlorine gas reacts with potassium iodide to form potassium chloride and iodine.
Cl2(g) + 2 KI → 2 KCl + I2
4) Propane (C3H8) burns with oxygen to form carbon dioxide and water vapor.
C3H8 + 5 O2 → 3CO2 + 4 H2O
5) Liquid water is decomposed with electricity to form hydrogen gas and oxygen gas.
H2O(l) → H2(g) + O2(g)
UNIT 8
Practice Test
Name _____________________________
page 2
E) Demonstrate that you can predict the products of a reaction by writing a
balanced reaction equation for each of the following: (ONE of these results in “no
reaction”.
1) Calcium reacts with oxygen.
2 Ca + O2 → 2 CaO
2) Lithium chloride reacts with silver nitrate. (double displacement reaction)
LiCl + AgNO3 → LiNO3 + AgCl↓
4) Gold reacts with hydrochloric acid (HCl).
Au + HCl → NO REACTION
5) Aluminum bromide is electrolyzed.
2 AlBr3 →(electricity) 2 Al + 3 Br2
6) Strontium iodide reacts with bromine.
SrI2 + Br2 → SrBr2 + I2
7) Sodium hydroxide reacts with sulfuric acid (H2SO4).
2 NaOH + H2SO4 → 2 H2O + Na2SO4
8) Hydrogen reacts with fluorine.
H2 + F2 → 2 HF
9) Methane (CH4) burns.
CH4 + 2 O2 → CO2 + 2 H2O
UNIT 8
Practice Test
Name _____________________________
page 3
F) Solve the following problems. Show as much work as possible and circle your
answer.
1) How much silver can be recovered by reacting 14 g of aluminum with excess silver
nitrate?
Al + 3 AgNO3 → 3 Ag + Al(NO3)3
14 g Al/(27.0 g/mol) = 0.519 mol Al
0.519 mol Al x (3 mol Ag/1 mol Al) = 1.56 mol Ag
1.56 mol Ag x (107.9 g/mol) = 170 g Ag
2) What is the percentage yield of the reaction in Question #1 if 12 g of silver is
recovered?
Percentage yield = actual yield/experimental yield
= 12 g/170 g
= 7.1%
3) How much lead(II) chromate can be produced by reacting 2.22 g of lead(II) nitrate
with 4.57 g of potassium chromate?
unbalanced reaction equation:
Pb(NO3)2 +
K2CrO4 
PbCrO4 + 2 KNO3
Pb(NO3)2: 207.2 amu + (2x14.0 amu) + (6 x 16.0 amu) = 331.2 g/mol
K2CrO4: (2x39.1 amu) + 52.0 amu + (4x16.0 amu) = 194.2 g/mol
PbCrO4: 207.2amu + 52.0amu + (4x16.0 amu) = 323.2 g/mol
2.22 g Pb(NO3)2/(331.2 g/mol) = 0.006703 mol Pb(NO3)2
0.006703 mol Pb(NO3)2 x (1 mol PbCrO4/1 mole Pb(NO3)2) = 0.006703 mol PbCrO4
Limiting reagent: 0.006703 mol PbCrO4 x (323.2 g/mol) = 2.17 g PbCrO4
4.57g K2CrO4/(194.2 g/mol) = 0.02353 mol K2CrO4
0.02353 mol K2CrO4 x (1 mol PbCrO4/1 mole K2CrO4) = 0.02353 mol PbCrO4
Excess reagent