Chemistry 11 (HL)
Unit 3 / IB Topics 1.3-1.5
Unit 3 Review: Quantities in Chemical Reactions
(aka Stoichiometry)
Unit 3 Topics:
Balanced Chemical Reactions and Mole Ratios
Mass Relationships in Chemical Reactions
Yield of a Reaction – Theoretical Yield, Actual Yield, % Yield
Limiting and Excess Reactants
Concentrations of Solutions (molarity)
Preparation of Stock Solutions
Calculations for Dilutions
Stoichiometry in Reactions Involving Aqueous Solutions
Pressure and Temperature; Standard Conditions for Gases
Avogadro’s Law
Law of Combining Volumes
Molar Volume
Ideal Gas Law and Related Problems
Gas Laws for a Fixed Mass of Gas:
- Boyle’s Law, Charles’ Law, Gay-Lussac Law, Combined Gas Law
- describe relationships in words, graphs and through calculations
Stoichiometry in Reactions Involving Gases
Data Provided: Periodic Table
Pressure Conversions:
Gas constant:
5
1 atm = 1.01 x 10 Pa = 760 mm Hg
-1 -1
R = 8.31 J mol K
PAPER 1 STYLE QUESTIONS – DO NOT USE A CALCULATOR
1.
2.
3
–3
What volume (in dm ) of 0.30 mol dm NaCl solution can be prepared from 0.060 mol of
solute?
A.
0.018
B.
0.20
C.
0.50
D.
5.0
Consider the following equation.
2C4H10(g) + 13O2(g)  8CO2(g) + 10H2O(l)
How many moles of CO2(g) are produced by the complete combustion of 58 g of butane,
C4H10(g)?
A.
4
B.
8
C.
12
D.
16
3.
6.0 moles of Fe2O3(s) reacts with 9.0 moles of carbon in a blast furnace according to the
equation below.
Fe2O3(s) + 3C(s) → 2Fe(s) + 3CO(g)
What is the limiting reagent and hence the theoretical yield of iron?
A.
B.
C.
D.
limiting reagent
Fe2O3
Fe2O3
carbon
carbon
theoretical yield of iron
6.0 mol
12.0 mol
9.0 mol
6.0 mol
p. 1
Chemistry 11 (HL)
4.
5.
Unit 3 / IB Topics 1.3-1.5
+
Which solution contains the smallest amount of H ions?
3
–3
3
–3
A.
10.0 cm of 0.250 mol dm HCl
B. 20.0 cm of 0.250 mol dm HCl
3
–3
3
–3
C.
10.0 cm of 0.500 mol dm HCl
D. 10.0 cm of 0.250 mol dm H2SO4
–3
What volume of 0.500 mol dm sulfuric acid solution is required to react completely with 10.0 g
of calcium carbonate according to the equation below?
CaCO3(s) + H2SO4(aq)  CaSO4(aq) + H2O(l) + CO2(g)
A.
6.
100 cm
3
B.
200 cm
3
C.
300 cm
3
D.
400 cm
3
–3
What volume of 0.500 mol dm HCl(aq) is required to react completely with 10.0 g of calcium
carbonate according to the equation below?
CaCO3(s) + 2HCl(aq) → CaCl2(aq) + H2O(l) + CO2(g)
A.
7.
2
B.
C.
300 cm
3
D.
400 cm
3
10
C.
250
D.
585
200 cm
3
B.
300 cm
3
C.
1200 cm
3
D.
3
1800 cm
3
3
1 dm of a gas in a container at -73˚C is allowed to expand to 1.5 dm . What must the temperature be
increased to so that the pressure remains constant?
-36˚C
B.
0˚C
C.
27˚C
D.
73˚C
Which of the following conditions would allow 1.60 g of oxygen gas to reach a maximum
pressure
high
low
high
low
volume?
temperature
low
high
high
low
Which gas would exert the greatest pressure at standard temperature?
A.
B.
C.
D.
12.
3
3
A.
B.
C.
D.
11.
200 cm
The pressure on 600 cm of gas is increased from 100 kPa to 300 kPa at constant temperature. What
will the new volume of gas be?
A.
10.
B.
3
A.
9.
3
A sealed flask contains 250 cm of gas at 35˚C and atmospheric pressure. The flask is then heated to
350˚C. The pressure of the gas will increase by a factor of about:
A.
8.
100 cm
3
3.2 g of oxygen gas occupies 0.50 dm
3
1.4 g of nitrogen gas occupies 0.50 dm
3
0.2 g of hydrogen gas occupies 1.0 dm
3
2.2 g of carbon dioxide gas occupies 0.50 dm
3
Which of the following gases at STP would occupy 2.24 dm ?
A.
0.20 g H2
B.
0.10 g O2
C.
0.10 g CO2
D. 0.22 g CO2
p. 2
Chemistry 11 (HL)
13.
Unit 3 / IB Topics 1.3-1.5
3
What is the mass of 11.2 dm of nitrogen gas under standard conditions?
A.
11.2 g
B. 0.50 g
C.
2.0 g
D. 14 g
PAPER 2 STYLE QUESTIONS
14.
0.502 g of an alkali metal sulfate is dissolved in water and excess barium chloride solution,
BaCl2(aq) is added to precipitate all the sulfate ions as barium sulfate, BaSO4(s). The
precipitate is filtered and dried and weighs 0.672 g.
(a)
Calculate the amount (in mol) of barium sulfate formed. (2)
(b)
Determine the amount (in mol) of the alkali metal sulfate present. (1)
(c)
Determine the molar mass of the alkali metal sulfate and state its units. (2)
(d)
Deduce the identity of the alkali metal, showing your workings. (2)
(e)
Write an equation for the precipitation reaction, including state symbols. (2)
(Total 9 marks)
15.
State and explain what would happen to the pressure of a given mass of gas when its absolute
temperature and volume are both doubled. (Total 3 marks)
16.
A toxic gas, A, consists of 53.8% nitrogen and 46.2% carbon by mass. At 273 K and
5
3
1.01×10 Pa, 1.048 g of A occupies 462 cm . Determine the empirical formula of A.
Calculate the molar mass of the compound.
(Total 2 marks)
17.
The reaction below represents the reduction of iron ore to produce iron.
2Fe2O3 + 3C  4Fe + 3CO2
A mixture of 30 kg of Fe2O3 and 5.0 kg of C was heated until no further reaction occurred.
Calculate the maximum mass of iron that can be obtained from these masses of reactants.
(Total 5 marks)
18.
(a)
(b)
(c)
19.
Write an equation for the formation of zinc iodide from zinc and iodine. (1)
100.0 g of zinc is allowed to react with 100.0 g of iodine producing zinc iodide.
Calculate the amount (in moles) of zinc and iodine, and hence determine which reactant
is in excess. (3)
Calculate the mass of zinc iodide that will be produced. (1)
Potassium hydroxide and calcium chloride solutions are mixed together, and a hydroxide
precipitate forms.
a)
Write the complete balanced chemical equation for this reaction.
b)
If you mix 45.0 mL of 0.85 M potassium hydroxide with excess calcium chloride,
what mass of precipitate should form?
20.
Freon-12, CCl2F2, is prepared from CCl4 by reaction with HF. HCl is the other product of this
reaction. What is the percent yield of a reaction in which 12.5 g of Freon-12 is produced from
32.9 g of carbon tetrachloride?
21.
The mass of H2 produced by reaction of 1.80 g Al and 6.00 g of sulfuric acid is 0.112 g. What
is the percent yield?
Al + H2SO4 ⇒ Al2(SO4)3 + H2
p. 3
Chemistry 11 (HL)
Unit 3 / IB Topics 1.3-1.5
22.
An experiment requires a 0.125 mol/L solution of magnesium chloride. The stock bottle of
magnesium chloride only contains 42.5 g of the solid. What is the maximum volume of
solution that can be prepared?
23.
What is the new concentration of a solution if 300.0 mL of water is added to 100.0 mL of a
0.025 mol/L CaCl2 solution?
24. What is the density of ammonia gas, in g/L, at STP?
25.
What is the volume occupied by 0.38 mol of sulfur trioxide gas at STP? Show 2 different
ways of finding this value.
26.
50.00 cm3 of 0.400 mol dm-3 CaCl2 is mixed with 25.00 cm3 of 0.900 mol dm-3 AgNO3. A
precipitate of silver chloride, AgCl, forms and it is collected by filtration. The mass of the filter
paper before filtration was 1.250 g. After filtration and drying, the mass of the filter paper
was 4.205 g.
a)
Determine the limiting reactant.
b)
Calculate the theoretical yield of the precipitate that forms.
c)
Calculate the actual yield.
d)
Calculate the percentage yield.
e)
Calculate the mass of excess reactant that remains.
“PAPER 1” ANSWERS:
1
7
13
B
A
D
2
8
A
A
3
9
D
C
4
10
A
B
5
11
B
A
6
12
“PAPER 2” QUESTIONS - ANSWERS
14. a)
e)
0.00288 mol
b) ) 0.00288 mol
c) 174.3 g mol
K2SO4(aq) + BaCl2(aq)  BaSO4(s) + 2KCl(aq)
15.
overall there will be no change to the pressure;
double absolute temperature and the pressure doubles;
double volume and the pressure halves;
16.
a)
17.
mass of Fe = 21 kg
18.
a)
19.
1.4 g
20.
48.3%
21.
90.6%
23.
0.0060 M
24.
0.76 g/L
25.
8.5 L
b)
3.22 g
c)
2.995 g
EF = CN
b)
Mr = 51.9 g mol
Zn + I2 → ZnI2
26a) AgNO3
b)
-1
d) Ar = 39 ∴ metal = K
-1
Zn is excess
c) mass ZnI2 formed = 125.8 g
22.
d)
3.57 L
91.8%
e)
0.971 g
p. 4
D
A