Chemistry
Section
_____
Name:
CH 9-11 STUDY GUIDE
_____________________________
Date:
________________________
Short Answer.
1. List five indications of a chemical reaction.
Heat / light (energy)
Color change
Precipitate formaton
Odor
Gas evolution
2. List five things a chemical equation does not tell.
Exact amounts of reactants and products
Reaction speed
Thermodynamics
Reaction pathway (or mechanism)
Spontaneity
3. Balance the following formula equations and identify the type of each reaction as synthesis,
decomposition, single replacement, double replacement, or combustion:
(NH4)2S (aq) +
ZnCl2 (aq) → 2 NH4Cl (aq) +
ZnS (s) double replacement
2 Al (s) + 3 Cl2 (g) → 2 AlCl3 (s)
synthesis
2 H2O (l) → 2 H2 (g) +
decomposition
2 Al (s) +
Fe2O3 (s) →
O2 (g)
Al2O3 (s) + 2 Fe (s)
2 CH3OH (g) + 3 O2 (g) → 2 CO2 (g) + 4 H2O (l)
single replacement
combustion
4. Write the word, formula and balanced equations for the production of sodium hydroxide
and hydrogen gas by the addition of sodium metal to water.
Word: sodium + water → sodium hydroxide + hydrogen
Formula: Na (s) + H2O (l) → NaOH (aq) + H2 (g)
Balanced: 2 Na (s) + 2 H2O (l) → 2 NaOH (aq) + H2 (g)
5. Write the balanced, ionic, and net ionic equations for the production of copper (II)
hydroxide and sodium nitrate by the addition of sodium hydroxide to copper (II) nitrate.
Balanced: 2 NaOH (aq) + Cu(NO3)2 (aq) → Cu(OH)2 (s) + 2 NaNO3 (aq)
Ionic: 2 Na+(aq) + 2 OH– (aq) + Cu+(aq) + 2 NO3– (aq) → Cu(OH)2 (s) + 2 Na+(aq) + 2 NO3– (aq)
Net Ionic: Cu+(aq) + 2 OH– (aq) → Cu(OH)2 (s)
Created on 19 February 2014
6. How many water molecules are present in a sample of 12.85 g of water?
m = 12.85 g
μμ = 18.0153 g mol–1
12.85g
.
0.7133mol
7. Heating sodium bicarbonate yields water, carbon dioxide and sodium carbonate according
to the balanced equation: 2 NaHCO3 → Na2CO3 + CO2 + H2O. If 9.3378 g of CO2 are
produced, how many moles of water are produced?
Mass A
Moles A
Moles B
Mass B
This is a Mass A to Moles B roadmap (requires 2 conversion factors)
μμ CO2 = 44.010 g mol–1
9.3378g
.
2
2
2
0.21217molH2O
8. In sunlight, chlorophyll causes the following chemical reaction to occur in plants. If a
plant has 270. g of CO2 and 100. g H2O available, how many moles of carbohydrate
(C3H6O3) can be produced? (Hint: this is a limiting reactant problem.)
+
3 CO2
3 H2O
Mass A
→
Moles A
C3H6O3
+
Moles B
3 O2
Mass B
This is a roadmap that can be solved two ways:
Mass A to Moles B roadmap (2 conversion factors) twice and pick the smallest answer or
Mass A to Mass B roadmap, find the LR then do a Mass A to Moles B roadmap
This is the first method:
μμ CO2 = 44.010 g mol–1
μμ H2O = 18.0153 g mol–1
270. g
100. g
2
.
2
.
3
6
3
1.82molC3H6O3
3
1.85molC3H6O3
2
3
6
2
1.82 mol C3H6O3 since it is the smaller answer and therefore most limited
9. In the following balanced equation, if 12.0 moles of O2 (g) react to form 5.50 moles of
Al2O3, what is the percent yield of aluminum oxide in the reaction?
4 Al (s)
+
3 O2 (g)
Mass A
→
Moles A
2 Al2O3 (s)
Moles B
Mass B
This is a Moles A to Moles B roadmap followed by a % yield
12.0molO2
%yield
2
3
2
8.00molAl2O3
100%
.
2
3
.
2
3
100%
68.8%