Unit 5 Review

1 / 25

When the temperature is decreased on a closed system containing water and its vapor at equilibrium:

H₂O(l) + heat ⇌ H₂O(g)
1. In order to restore equilibrium, more liquid water evaporates
2. In order to restore equilibrium, water vapor condenses to form liquid water
3. No change occurs
This is the aqueous iron(III) thiocyanate equilibrium:

Fe³⁺(yellow) + SCN^-(colorless) ⇌ [FeSCN]²⁺(dark red)

If aqueous potassium thiocyanate is added to the solution at equilibrium:
1. No change in color occurs
2. The solution turns darker red
3. The solution becomes colorless
4. The solution becomes more yellow
The line that represents the activation energy (E_a) of this reaction is
1. Line B
2. Line C
3. Line A
4. Line D
The activation energy (E_a) of this reaction is
1. 240 kJ
2. 80 kJ
3. 40 kJ
4. - 80 kJ
5. 160 kJ
A precipitation reaction achieves equilibrium:

BaCl₂(aq) + Na₂SO₄(aq) ⇌ 2 NaCl(aq) + BaSO₄(s)

If barium chloride (BaCl₂) is added to the system, which change occurs?
1. The reaction shifts to the left, and some precipitate dissolves
2. The reaction shifts to the right, and more precipitate is produced
3. No change occurs
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. 0.80 moles per minute
2. 0.20 moles per minute
3. 1.6 moles per minute
4. 0.40 moles per minute
The line that represents the heat of reaction (ΔH, or ΔE) of this reaction is
1. Line A
2. Line C
3. Line D
4. Line B
An increase in temperature increases the rate of a chemical reaction by what means
1. Increasing collision frequency
2. Increasing collision energy
3. Increasing pressure
4. Decreasing activation energy
5. Increasing the concentration of reactants
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. 2.5 moles per second
2. 1 mole per second
3. 8 moles per second
4. 2 moles per second
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 left, toward reactants
2. No change occurs
3. In order to restore equilibrium, the reaction shifts right, toward products
In the reaction depicted in the diagram above,
1. the energy content of the products is greater than the energy content of the reactants
2. the energy content of the reactants is greater than the energy content of the products
3. the energy content of the reactants is the same as the energy content of the products
The process of dissolving Na₂SO₄ in water is known to be exothermic:

Na₂SO₄(s) ⇌ 2 Na⁺(aq) + SO₄^2-(aq) + heat

If the temperature of the solution is decreased, Na₂SO₄ becomes:
1. No change in solubility occurs
2. More soluble
3. Less soluble
When N₂ is removed from the following system at equilibrium:

3 H₂(g) + N₂(g) ⇌ 2 NH₃(g)
1. No change occurs
2. In order to restore equilibrium, the reaction shifts left, toward reactants
3. In order to restore equilibrium, the reaction shifts right, toward products
The reaction whose energy diagram is shown here is
1. isothermic
2. exothermic
3. endothermic
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. 0.2 moles per second
2. 2 moles per second
3. 1 mole per second
4. 5 moles per second
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. 1.20 moles per minute
2. 1.6 moles per minute
3. 0.80 moles per minute
4. 0.40 moles per minute
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. 4 moles per second
3. 0.5 moles per second
4. 2 moles per second
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 left, toward reactants
2. No change occurs
3. In order to restore equilibrium, the reaction shifts right, toward products
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 left, toward reactants
2. In order to restore equilibrium, the reaction shifts right, toward products
3. No change occurs
When the pressure is increased on a closed system containing water and its vapor at equilibrium:

H₂O(l) + heat ⇌ H₂O(g)
1. In order to restore equilibrium, more liquid water evaporates
2. In order to restore equilibrium, water vapor condenses to form liquid water
3. No change occurs
When the pressure is increased on the following system at equilibrium:

3 H₂(g) + N₂(g) ⇌ 2 NH₃(g)
1. No change occurs
2. In order to restore equilibrium, the reaction shifts right, toward products
3. In order to restore equilibrium, the reaction shifts left, toward reactants
The line that represents the heat of reaction (ΔH, or ΔE) of this reaction is
1. Line E
2. Line D
3. Line B
4. Line C
5. Line A
A beaker with a mixture of ice and water is maintained at equilibrium:

H₂O(s) + heat ⇌ H₂O(l)

If the temperature of the system is decreased:
1. No change occurs
2. Water freezes to form ice (shift to the left)
3. Ice melts to form liquid water (shift to the right)
If you were holding in your hand a test tube in which the reaction above is taking place, it would
1. feel cold, because energy is being absorbed
2. feel hot, because energy is being absorbed
3. feel cold, because energy is being released
4. feel hot, because energy is being released
Which of the following will increase the rate of a chemical reaction?
1. A decrease in surface area of reactants
2. An increase in concentration of reactants
3. An increase in pressure of gases
4. An increase in temperature