Unit Review

Question 1

The correct units for specific heat capacity are
A. J / (g·°C)
B. kJ / g·°C
C. kg / (J·°C)
D. °C / (g·J)

Answer 1

A

Question 2

Answer 2

572

Question 3

There are several electrical generating stations in Alberta that use the energy from burning coal to generate electricity. Assuming coal is pure carbon, the temperature increase in 1.00 t of water when it absorbs all the energy produced by the complete combustion of 1.00 kg of coal is calculated to be ______ °C.

Answer 3

7.82

Question 4

Which statements are true for exothermic reactions?

Answer 4

1, 2, 3, 5

Question 5

Which statements are true for endothermic reactions?

Answer 5

1, 2, 4, 6

Question 6

The energy barrier that must be overcome in order for a reaction to occur is referred to as the
A. activation energy
B. bond energy
C. enthalpy change
D. molar enthalpy

Answer 6

A

Question 7

Catalysts are an essential part of most industrial chemical processes. Which of the following statements about catalysts is false?
A. Catalysts are not consumed in the net reaction.
B. Catalysts increase the enthalpy of the products.
C. Catalysts increase the overall rate of a reaction.
D. Catalysts provide an alternative pathway for the reaction.

Answer 7

B

Question 8

Using a catalyst in a chemical reaction
A. increases the enthalpy change of the reaction
B. increases the activation energy of the reaction
C. decreases the enthalpy change of the reaction
D. decreases the activation energy of the reaction

Answer 8

D

Question 9

Answer 9

1442

Question 10

Answer 10

749

Question 11

Answer 11

A

Question 12

Glucose is an important natural product. Which of the following reactions involving glucose is endothermic?
A. Formation of glucose from its elements
B. Combustion of glucose
C. Cellular respiration of glucose
D. Photosynthesis involving glucose

Answer 12

D

Question 13

Match the appropriate energy change, labelled 1 to 5 in the graph, with the following reactions. Give your answers in the same order as the energy changes listed.
* enthalpy change for the forward reaction
* enthalpy change for the reverse reaction
* activation energy for the uncatalyzed reaction
* activation energy for the catalyzed reaction

Answer 13

3, 3, 1, 2

Question 14

From the graph above, match the appropriate sections, numbered 6 to 9, with the following statements. Give your answers in the same order as the statements.
* the activated complex for the uncatalyzed reaction
* the activated complex for the catalyzed reaction
* the conversion of kinetic energy into potential energy
* the same average chemical potential energy of entities with varying kinetic energy
___, ___, ___, and ___

Answer 14

8, 9, 7, 6

Question 15

Combustion of a hydrocarbon, cellular respiration, and photosynthesis have much in common. Which of the following is not common to all three reactions?
A. energy
B. CO₂ (g)
C. H₂O(l)
D. H₂O(g)

Answer 15

D

Question 16

Part of the character of chemicals is their thermal stability.
List the following organic compounds in order of increasing stability.
1. sucrose, C₁₂H₂₂O₁₁(s)
2. ethanoic acid, CH₃COOH(l)
3. ethanol, C₂H₅OH(l)
4. glucose, C₆H₁₂O₆(s)

Answer 16

3, 2, 4, 1

Question 17

Enumerate four factors that influence the rate of a chemical reaction.

Answer 17

Factors that influence the rate of a chemical reaction [four only required]
- temperature
- surface area of a liquid or solid if it is in the reaction
- the presence of a catalyst
- the type of reactants (influencing bond and activation energies) pressure (if a reactant or product is a gas)

Question 18

The reaction equation
A + B → C + D ΔrH = -250 kJ
represents a hypothetical reaction. Illustrate the reaction with an energy pathway diagram showing the catalyzed and uncatalyzed reactions, given that the activation energy is twice as large for the uncatalyzed reaction as for the catalyzed reaction.

Answer 18

Question 19

Answer 19

Question 20

Answer 20

Question 21

Answer 21

Question 22

Answer 22

Question 23

Answer 23

Question 24

Catalysts are one of many technological solutions used to reduce greenhouse gas (GHG) emissions.
(a) List the four GHGs that research shows have the most effect on global warming.
(b) From research, which of carbon dioxide or methane is found to have the larger global warming potential (GWP)?
(c) The catalysts used in catalytic converters in cars are from what class of elements in the periodic table?

Answer 24

(a) Water vapour, carbon dioxide, methane, and ozone have the highest global warming potential (GWP).
(b) Methane has a larger warming potential than CO2 (21 to 1). [See Chapter 10, Table 3 on page 472 of the Student Book.]
(c) Transition metals are common catalysts.

Question 25

(a) Table 1 shows the increase in per capita GHG
emissions from fossil fuel combustion and production since 1990. What is the percentage increase in this time?
(b) Research recent GHG emissions in Environment Canada’s Greenhouse Gas Inventory. Graph the per capita emissions over the last fifteen years or so. Comment on the trends you observe.
(c) What is the Canadian GHG emission target in tonnes per capita? If every one of us meets this target, what will be the percentage reduction in GHG emissions? Relate this to the graph you plotted in (b).

Answer 25

Question 26

List five ways by which you can personally reduce GHG emissions.

Answer 26

Question 27

Why do most Canadians (as indicated by polls) want to reduce the emission of GHGs?

Answer 27

The majority of Canadians polled see global warming (climate change) as a significant threat to themselves and their families. Furthermore, most believe that other important issues such as education and healthcare won’t matter if the threat of global warming (climate change) is ignored. One could also hypothesize that sustainable development to save resources for future generations is important to most Canadians.

Question 28

Answer 28

Question 29

Ethanoic acid (acetic acid) is an important industrial
chemical that is manufactured from the reaction of
methanol and carbon monoxide using rhodium or iridium catalysts.
(a) Write the balanced chemical equation for the
industrial production of ethanoic acid.
(b) Sketch a chemical potential energy diagram, and
label the enthalpy change.
(c) Sketch an energy pathway diagram, and label the
activation energies for the uncatalyzed and catalyzed
reactions.
(d) Provide the scientific explanation and the
technological purpose for using a catalyst.

Answer 29

Question 30

Answer 30

Question 31

Answer 31

(a) Some provinces and territories, including British Columbia, Yukon Territory, Manitoba, Quebec, and Newfoundland, produce large quantities of hydroelectric power compared with other methods of producing electricity. This is probably because these provinces have a highly suitable geography for dams, but have little access to oil reserves. Other provinces with lower hydroelectric power generation have either unsuitable geography for dams or an abundant alternate energy source such as natural gas or coal. A trend apparent in Table 2 is that relative hydroelectric use decreased between 1994 and 2002 in all provinces and territories except British Columbia and Yukon Territory.
(c) Alberta has the second lowest percentage of hydroelectric generation, probably because Alberta has an abundance of fossil fuels, e.g., natural gas and (in particular) coal. The lack of access to areas that are suitable for hydroelectric dams may be another reason. [Alberta also produces more wind power electricity than any other province in Canada, although the percentage of the total is small.]
(d) Pros
Ɣ There are no GHG emissions from burning fossil fuels (after the dam is well established).
Ɣ This is a renewable energy resource (driven by the water cycle).
Ɣ There are no waste products (as from fossil fuel and nuclear power stations).
Cons
Ɣ Ecosystems are destroyed and replaced by human-made reservoirs of water.
Ɣ GHG emissions occur from the decay of vegetation below the water surface.
Ɣ Seepage of water can occur from the dam site to surrounding lands.
Ɣ Fish may be affected during their annual spawning.
Ɣ Dams can break, creating danger for downstream plants and animals (including people).
Ɣ Downstream water needs are affected by the need for water at the hydroelectric dam.
(e) Economic:
Ɣ Pro: Hydroelectric power is a self-sustaining energy source that has very low fuel costs; whereas the cost of fossil fuels is continually increasing.
Ɣ Con: The initial cost of change (from fossil fuel to hydro) in terms of infrastructure (building large dams) is very high.
Political:
Ɣ Pro: This allows Canada to meet Kyoto treaty obligations.
Ɣ Con: will probably face stiff political opposition from the large oil and gas companies.
Technological:
Ɣ Pro: The technology exists to build large dams on rivers; microdams can supply individual homes.
Ɣ Con: The technology cannot overcome seepage into geological features, due to high pressure created by tall dams.

Question 32

People living in different regions of Canada use (or in the past have used) different fuels for cooking and for heating their homes. Enumerate five different fuels used by peoples in different parts of Canada—north to south and west to east.

Answer 32

Different fuels, used at various times by people in Canada, include wood, coal, natural gas, propane, fuel oil, animal oil, plant oil, and dried animal dung. Oil derived from whale blubber was traditionally used for cooking and lamp oil by the Inuit. Kerosene, coal oil, and naphtha have been used for lamps, along with candles (a hydrocarbon) for light and heat.

Question 33

Compare methane and propane as fuels. Establish at least four criteria for evaluating these fuels. Provide quantitative and/or qualitative information for each criterion. Finally, provide a personal choice based upon the information compiled and upon your values. Share your findings as an audio-visual presentation.

Answer 33

Cost: [The cost will vary and can be determined by enquiring at the provider; e.g., 5.81 $/GJ for natural gas and 6.10 $/GJ for propane for August, 2006.] Although natural gas is generally less expensive than propane, the cost of installing a gas pipeline in rural areas makes the cost of heating a home by natural gas prohibitive. Therefore, rural homeowners often opt for installing a large propane tank that is periodically refilled. This problem is similar to that encountered when deciding whether to fuel a gas barbecue with propane or natural gas (even in a city).
Accessibility/Supply: As indicated above, access to natural gas and to propane varies, with the supply of natural gas being more of a problem. Propane as a fuel for cars is currently more accessible than natural gas.
Energy/gram: Propane produces 46.33 kJ/g, whereas methane produces 50.00 kJ/g. Methane is therefore more useful, according to this criterion. [See answer to question 29.]
Emissions: Both fuels produce GHG, including CO2 and H2O. Propane produces 2.99 g CO2/g fuel, whereas methane produces 2.74 g CO2/g fuel when completely combusted. Therefore, methane is slightly better ranked for this criterion.
Infrastructure: The infrastructure for supplying natural gas for homes is widely in place. The infrastructure for supplying propane for cars and trucks is more in place than for supplying natural gas to vehicles. (This is not true for countries like Brazil where the infrastructure is in place for supplying gasoline, ethanol, and/or natural gas for automobiles.)

Question 34

Answer 34

Question 35

Answer 35

Question 36

Over the years there have been many “free energy” devices or “energy machines” advertised on the Internet. The energy output of these devices is claimed to be greater than the energy input. As a skeptic, what kind of authorities would you consult and/or what kinds of tests would you advocate to test these claims?

Answer 36

Any claim of “free energy” should be met with considerable skepticism. I would want to be sure that several independent teams of scientists had repeated the inventor’s experimental design, and obtained similar results. I would expect the design to include some method for measuring the quantity of energy in the system or device both before and after the “production” of energy. The law of conservation of energy is well established and supported by over a hundred years of evidence. Considerable evidence would be required to falsify this widely accepted scientific law.