Unit 7 Review - Thermochemistry, Kinetics and Equilibrium

Values for the specific heat of water, as well as the latent heat of fusion and latent heat vaporization for water are given on back of the California CST periodic table.

The specific heat of aluminum is 0.90 J/g·°C. How much energy is required to raise the temperature of 10 grams of aluminum from 10°C to 20°C?
1. 90 joules
2. 0.009 joules
3. 111 joules
4. 100.9 joules
A 100 gram sample of a metal undergoes a temperature change from 20°C to 50° after absorbing 1500 J of heat. What is the specific heat of the metal?
1. 0.5 J/g·°C
2. 2 J/g·°C
3. 4.5 x 10⁶ J/g·°C
4. 0.25 J/g·°C
How many joules of heat energy are required to raise the temperature of 20 grams of water by 50°C?
1. 4180 joules
2. 239.2 joules
3. 0.00418 joules
4. 19.7 joules
What energy change has occured occurred when 500 grams of water cools from 35°C to 25°C?
1. -20 900 joules
2. 20 900 joules
3. -1196 joules
4. 11.96 joules
How many joules are required to vaporize 10 grams of water at its boiling point?
1. 22 600 joules
2. 226 joules
3. 0.0044 joules
4. 2270 joules
How much energy must be removed from 2 grams of water at 0°C to convert the water to ice?
1. 668 joules
2. 167 joules
3. 0.00599 joules
4. 336 joules
What mass of ice at 0°C can be melted by the addition of 1670 joules of heat?
1. 5 grams
2. 0.2 grams
3. 8350 grams
4. 1670 grams
How many grams of water at 100°C can be converted to steam by the addition of 565 joules of heat?
1. 0.25 grams
2. 4 grams
3. 56 500 grams
4. 1 276 900 joules
A 100 gram piece of brass at a temperature of 100°C is dropped into 100 grams of water that has a temperature of 20°C. Which of the following describes what happens next?
1. They come to equilibrium at a temperature above 60°C, because the metal has a higher specific heat than does the water.
2. They come to equilibrium at a temperature above 60°C, because the metal has a lower specific heat than does the water.
3. They come to equilibrium at a temperature below 60°C, because the metal has a higher specific heat than does the water.
4. They come to equilibrium at a temperature below 60°C, because the metal has a lower specific heat than does the water.
When a piece of gold (specific heat 0.13 J/g·°C) and a piece of iron (specific heat 0.46 J/g·°C) each absorb equal amount of heat
1. the gold will end up with the higher final temperature
2. the iron will end up with the higher final temperature
3. they will end up at the same final temperature
Which of the following phase changes involve the addition (absorption) of heat?
1. condensation
2. vaporization
3. freezing
4. melting
Which of the following phase changes involve the removal (release) of heat?
1. condensation
2. vaporization
3. freezing
4. melting
When you mixed magnesium with hydrochloric acid in the lab, the reaction got warmer. This indicates that
1. the reaction is exothermic, because energy was released
2. the reaction is endothermic, because energy was released
3. the reaction is exothermic, because energy was absorbed
4. the reaction is endothermic, because energy was absorbed
When you mixed baking soda with citric acid in the lab, the reaction got colder. This indicates that
1. the reaction is exothermic, because energy was released
2. the reaction is endothermic, because energy was released
3. the reaction is exothermic, because energy was absorbed
4. the reaction is endothermic, because energy was absorbed
In an exothermic reaction,
1. the energy content of the reactants is greater than the energy content of the products
2. the energy content of the reactants is less than the energy content of the products
3. the energy content of the reactants is the same as the energy content of the products
In an endothermic reaction,
1. the energy content of the reactants is greater than the energy content of the products
2. the energy content of the reactants is less than the energy content of the products
3. the energy content of the reactants is the same as the energy content of the products
In the diagram above, the energy content of the reactants is
1. 80 kilojoules
2. 160 kilojoules
3. 240 kilojoules
In the diagram above, the energy content of the products is
1. 80 kilojoules
2. 160 kilojoules
3. 240 kilojoules
In the diagram above, the activation energy (E_a) would be calculated by doing which of the following?
1. 240 kilojoules - 160 kilojoules = 80 kilojoules
2. 240 kilojoules - 80 kilojoules = 160 kilojoules
3. 80 kilojoules + 160 kilojoules = 240 kilojoules
4. 160 kilojoules - 80 kilojoules = 80 kilojoules
In the diagram above, the heat of reaction (ΔH) would be calculated by doing which of the following?
1. 240 kilojoules - 160 kilojoules = 80 kilojoules
2. 240 kilojoules - 80 kilojoules = 160 kilojoules
3. 240 kilojoules + 160 kilojoules = 240 kilojoules
4. 160 kilojoules - 80 kilojoules = 80 kilojoules
In the diagram above, the energy content of the products
1. is the same as the energy content of the reactants
2. is the greater than the energy content of the reactants
3. is less than the energy content of the reactants
The diagram above depicts a reaction that is
1. endothermic
2. exothermic
3. isothermic
Equal masses of each of the following substances absorb an equal amount of energy. Which substance experiences the greatest temperature increase?

Iron; specific heat = 0.449 J/(g·ºC)
Aluminum; specific heat = 0.897 J/(g·ºC)
Liquid water; specific heat = 4.18 J/(g·ºC)
Ice; specific heat = 2.06 J/(g·ºC)
1. Iron
2. Aluminum
3. Liquid water
4. Ice
Catalysts increase the rate of a chemical reaction by what means?
1. Increasing collision energy
2. Increasing the concentration of reactants
3. Lowering activation energy
4. Increasing temperature
Which of the following will burn most rapidly?
1. Solid alcohol
2. Liquid alcohol
3. Vaporized alcohol
4. All burn at the same rate
In chemical reactions, electricity, a spark, and sunlight are all ways in which _______________ may be provided.
1. activation energy
2. reactants
3. products
4. catalysts
For an effective collision to take place, there must be:
1. A sufficiently hard collision
2. A correctly oriented collision
3. A catalyst present
4. No products present
5. High pressure
Which of the following is guaranteed to slow down the rate of a chemical reaction?
1. Addition of a catalyst
2. Decreasing the temperature
3. Increasing the temperature
4. Decreasing the concentration of the reactants
5. Increasing the pressure
At 25 ºC, a certain reaction is able to produce 0.80 moles of product per minute? At what rate might the product be produced at 35 ºC?
1. 0.40 moles per minute
2. 1.6 moles per minute
3. 0.20 moles per minute
4. 0.80 moles per minute
At 25 ºC, a certain reaction is able to produce 0.80 moles of product per minute? At what rate might the product be produced at 15 ºC?
1. 0.40 moles per minute
2. 1.6 moles per minute
3. 1.20 moles per minute
4. 0.80 moles per minute
In this chemical reaction:

2 HCl(aq) + Mg(s) <--> MgCl₂(aq) + H₂(g) + heat
1. energy is given off, so the reaction is endothermic
2. energy is given off, so the reaction is exothermic
3. energy is absorbed, so the reaction is endothermic
4. energy is absorbed, so the reaction is exothermic
Given the following reaction:

P₄(s) + 5 O₂(g) --> 2 P₂O₅(s)

If the intial rate of the reaction consumes 1 mole of phosphorus, P₄, per second, what is the rate at which oxygen, O₂, is consumed initially?
1. 1 mole per second
2. 2 moles per second
3. 0.2 moles per second
4. 5 moles per second
Given the following reaction:

P₄(s) + 5 O₂(g) --> 2 P₂O₅(s)

If the intial rate of the reaction consumes 1 mole of phosphorus, P₄, per second, what is the rate at which diphosphorus pentoxide, P₂O₅, is formed initially?
1. 1 mole per second
2. 2 moles per second
3. 0.2 moles per second
4. 5 moles per second
Given the following reaction:

C₃H₈(g) + 5 O₂(g) --> 3 CO₂ + 4 H₂O(g)

If the intial rate of the reaction produces 2 moles of water vapor, H₂O, per second, what is the rate at which carbon dioxide, CO₂, is formed initially?
1. 3 moles per second
2. 2 moles per second
3. 2.67 moles per second
4. 1.5 moles per second
Given the following reaction:

C₃H₈(g) + 5 O₂(g) --> 3 CO₂ + 4 H₂O(g)

If the intial rate of the reaction produces 2 moles of water vapor, H₂O, per second, what is the rate at which oxygen, O₂, is consumed initially?
1. 1 mole per second
2. 2 moles per second
3. 8 moles per second
4. 2.5 moles per second
Given the following reaction:

C₃H₈(g) + 5 O₂(g) --> 3 CO₂ + 4 H₂O(g)

If the intial rate of the reaction produces 2 moles of water vapor, H₂O, per second, what is the rate at which propane, C₃H₈, is consumed initially?
1. 1 mole per second
2. 2 moles per second
3. 4 moles per second
4. 0.5 moles per second
Given the following reaction:

2 H₂(g) + O₂(g) --> 2 H₂O

As this reaction takes place:
1. the quantity of water vapor, H₂O(g), decreases
2. the quantities of hydrogen, H₂, and oxygen, O₂, decrease
3. the quantities of hydrogen, H₂, and oxygen, O₂, increase
4. the quantity of hydrogen, H₂, increases and the quantity of oxygen, O₂, decreases
Given the following reaction:

H₂(g) + Cl₂(g) --> 2 HCl

As this reaction takes place:
1. HCl is produced at the same rate that H₂ is consumed
2. H₂ and Cl₂ are consumed at the same rate
3. HCl is produced at the twice the rate that Cl₂ is consumed
4. HCl is produced at the half the rate that Cl₂ is consumed
When extra NH₃ is added to the following system at equilibrium:

3 H₂(g) + N₂(g) <--> 2 NH₃(g)
1. In order to restore equilibrium, the reaction shifts right, toward products
2. In order to restore equilibrium, the reaction shifts left, toward reactants
3. No change occurs
When N₂ is removed from the following system at equilibrium:

3 H₂(g) + N₂(g) <--> 2 NH₃(g)
1. In order to restore equilibrium, the reaction shifts right, toward products
2. In order to restore equilibrium, the reaction shifts left, toward reactants
3. No change occurs
When H₂ is added to the following system at equilibrium:

3 H₂(g) + N₂(g) <--> 2 NH₃(g)
1. In order to restore equilibrium, the reaction shifts right, toward products
2. In order to restore equilibrium, the reaction shifts left, toward reactants
3. No change occurs
When the pressure is increased on the following system at equilibrium:

3 H₂(g) + N₂(g) <--> 2 NH₃(g)
1. In order to restore equilibrium, the reaction shifts right, toward products
2. In order to restore equilibrium, the reaction shifts left, toward reactants
3. No change occurs
When the pressure is decreased on the following system at equilibrium:

3 H₂(g) + N₂(g) <--> 2 NH₃(g)
1. In order to restore equilibrium, the reaction shifts right, toward products
2. In order to restore equilibrium, the reaction shifts left, toward reactants
3. No change occurs
When the temperature is decreased on the following system at equilibrium:

2 HCl(aq) + Mg(s) <--> MgCl₂(aq) + H₂(g) + heat
1. In order to restore equilibrium, the reaction shifts right, toward products
2. In order to restore equilibrium, the reaction shifts left, toward reactants
3. No change occurs
When the temperature is increased on the following system at equilibrium:

2 HCl(aq) + Mg(s) <--> MgCl₂(aq) + H₂(g) + heat
1. In order to restore equilibrium, the reaction shifts right, toward products
2. In order to restore equilibrium, the reaction shifts left, toward reactants
3. No change occurs
When the temperature is decreased on the following system at equilibrium:

2 HCl(aq) + Mg(s) <--> MgCl₂(aq) + H₂(g) + heat
1. In order to restore equilibrium, the reaction shifts right, toward products
2. In order to restore equilibrium, the reaction shifts left, toward reactants
3. No change occurs