Chapter 10
Review
Understanding Concepts
1. From his experimental work with gases, John Dalton
developed the law of partial pressures. State Dalton’s
law of partial pressures
(a) in a sentence;
(b) as a mathematical equation.
2. Using the kinetic molecular theory, explain Dalton’s law
of partial pressures.
3. A sample of sour natural gas contains gases with the
following partial pressures: 230 kPa methane, 13 kPa
ethane, and 7 kPa hydrogen sulfide. Calculate the total
pressure of the sour natural gas mixture.
4. Oxygen gas generated by the decomposition of potassium chlorate is collected at SATP by the downward displacement of water. Calculate the partial pressure of the
oxygen, assuming it is saturated with water vapour.
(The vapour pressure of water is given in Table 3 of
Section 10.1.)
5. From his experimental work with chemical reactions
involving gases, Joseph Gay-Lussac developed the law of
combining volumes.
(a) Using your own words, state the law of combining
volumes in a sentence.
(b) Use the law of combining volumes to predict the
volume of each gas produced when 5.00 L of
oxygen gas is consumed in the complete combustion of trinitrotoluene, TNT. Assume all gases are
measured at the same temperature and pressure.
(b) Bulbs heat up as they generate light. What will the
pressure be inside a light bulb when the temperature rises to 200°C?
(c) A steel tank contains 50.0 kg of compressed argon.
If one fluorescent tube has an internal volume of
0.915 L, how many tubes can be filled from the
tank? Assume a pressure of 100.4 kPa inside each
tube when the temperature is 20°C.
9. One of the major sources of atmospheric sulfur dioxide,
SO2(g), is the extraction of metals from their sulfide
ores. Metal extraction often involves heating the metal
sulfide in air to form the metal oxide and sulfur
dioxide, for example,
2 ZnS(s) 3 O2(g) → 2 ZnO(s) 2 SO2(g)
What volume of sulfur dioxide at SATP is produced by the
reaction of 1.00 t of zinc sulfide with an excess of oxygen?
10. Sulfur dioxide released to the atmosphere forms acid
rain, but it can also attack calcium carbonate directly
(as seen in the sculpture in Figure 1).
2 CaCO3(s) 2 SO2(g) O2(g) → 2 CaSO4(s) 2 CO2(g)
If 500 kL of sulfur dioxide reacts at STP,
(a) What volume of carbon dioxide gas at STP is produced?
(b) What mass of calcium carbonate is consumed?
4 C7H5(NO2)3(s) 21 O2(g) → 28 CO2(g) 6 N2(g) 10 H2O(g)
6. Amedeo Avogadro proposed an idea to explain the law
of combining volumes. Avogadro’s idea is sometimes
called a principle, a hypothesis, a law, and a theory. Is
Avogadro’s idea empirical or theoretical? Explain your
answer.
7. Disastrous explosions have resulted from the unsafe
storage and handling of the fertilizer ammonium
nitrate, which can decompose rapidly.
2 NH4NO3(s) → 2 N2(g) 4 H2O(g) O2(g)
What volume of gases measured at SATP is produced by
the decomposition of 1.00 mol of ammonium nitrate?
8. Argon is used in incandescant light bulbs and fluorescent tubes at a pressure of 400 Pa above atmospheric
pressure.
(a) What amount of argon is required to fill a 125-mL
light bulb when the temperature is 20°C and
atmospheric pressure is 100.0 kPa?
492 Chapter 10
Figure 1
11. Sulfur trioxide in the atmosphere reacts with rainwater
to form sulfuric acid.
SO3(g) H2O(l) → H2SO4(aq)
If 1.00 t of atmospheric sulfur trioxide dissolves in rainwater, what volume of 0.12 mmol/L sulfuric acid could
be formed?
12. In a demonstration of the decomposition of water by
electrolysis, 50.0 mL of hydrogen gas is produced at
23°C and 103 kPa.
(a) What volume of oxygen gas is produced at the same
temperature and pressure?
(b) What would be the volume of hydrogen produced
if it was measured at STP?
(c) What mass of water is decomposed?
13. After 2.00 mol of N2(g) and 3.00 mol of H2(g) are added
to a reaction vessel, the total pressure is measured at
200 kPa. Calculate the partial pressure of each gas in
the vessel.
14. How does the molar volume of a gas change
(a) when temperature increases?
(b) when pressure increases?
Applying Inquiry Skills
15. Complete the Prediction, Analysis, and Evaluation sections of the following investigation report.
Question
What is the molar volume of propane, C3H8(g), at STP?
Prediction
(a) Predict the answer to the Question and state the
basis for your Prediction.
Experimental Design
A small propane cylinder sold for home maintenance
applications provides the propane gas that is collected
at ambient pressure by water displacement.
Evidence
initial mass of propane cylinder 426.79 g
final mass of propane cylinder 424.92 g
volume of gas collected 1065 mL
ambient pressure 98.23 kPa
ambient temperature 21.0°C
Analysis
(b) Based on the Evidence, what is the answer to the
Question? (The pressure must be adjusted to correct for the vapour pressure of water; see Table 3,
Section 10.1.)
Evaluation
(c) Calculate the percentage difference. Does the
answer based on the Evidence agree with your predicted value?
(d) Based on your evaluation of the Prediction, evaluate the authority you used to make your
Prediction.
16. A cylinder of compressed gas is known to contain a
noble gas. Design an experiment to identify the gas by
its molar mass.
Making Connections
17. List one natural and one technological use or source for
each of the following gases:
(a) oxygen
(b) methane
(c) helium
(d) air
(e) water vapour
(f) carbon dioxide
18. In the 1930s, chemists produced a series of synthetic
chemicals called Freons. Some common Freons are
CFCl3(g), CF2Cl2(g), C2F3Cl3(g), and C2F4Cl2(g).
(a) What were some of the initial uses of Freons?
(b) Why has the production of Freons been banned in
many countries, including Canada?
(c) What volume does 1.00 kg of escaped CF2Cl2(g)
occupy at SATP?
19. Ethanethiol, C2H5SH(g), is a very smelly compound that
is added to natural gas so that gas leaks can be detected
easily. When the natural gas is burned, the ethanethiol
undergoes combustion as well:
2 C2H5SH(g) 9 O2(g) → 4 CO2(g) 6 H2O(g) 2 SO2(g)
(a) Calculate the volume at SATP of each gas produced
when 1.00 g of ethanethiol is burned.
(b) Discuss some of the risks and benefits of adding
ethanethiol to natural gas.
20. Ontario’s Air Quality Index (AQI) network includes 33
state-of-the-art air quality monitoring stations across
the province. Each AQI site monitors some or all of the
six most common air pollutants: sulfur dioxide, ozone,
nitrogen dioxide, total reduced sulfur compounds,
carbon monoxide, and suspended particles. Locate the
AQI station closest to your school, and research the
source of the most common pollutant and the health
risks associated with it. Prepare a one-page summary of
your findings.
Follow the links for Nelson Chemistry 11, Chapter 10
Review.
GO TO
www.science.nelson.com
Gas Mixtures and Reactions 493