Question 1

When a chemical system has reached equilibrium

Accepted Answer

At equilibrium, the rate of the forward and reverse reactions are equal, which is represented by the equilibrium constant. Choice A is incorrect because the reactions have not stopped, they are just occurring at the same rate. Choices B and C are incorrect as they suggest that one reaction is still proceeding, which is not the case at equilibrium. Choice E is also incorrect, as the equilibrium constant does not have a minimum value, but rather a specific value determined by the temperature and concentrations of the reactants and products.

Question 2

Identify the catalyst in the following three-step process for the decomposition of ozone. O₃(g)⇌ O₂(g)+ O(g)NO(g)+ O₃(g)→ NO₂(g)+ O₂(g)O(g)+ NO₂(g)→ O₂(g)+ NO(g)

Accepted Answer

NO(g) acts as a catalyst in the process for the decomposition of ozone. It participates in the reaction sequence but is regenerated in the final step, meaning it is not consumed in the overall reaction.

Question 3

Given that the following reaction is exothermic, which of the following sets of changes would cause the following system at equilibrium to shift to increase the number of N₂O₄(g)molecules? 2NO₂(g)⇌ N₂O₄(g)What observation would indicate that the reaction is at equilibrium in a closed container?

Accepted Answer

According to Le Chatelier's principle, when an equilibrium system is subjected to a stress, the system will shift in a way that opposes the stress. In this case, decreasing the volume of the container will increase the pressure, and the system will shift in the direction that has fewer moles of gas to reduce the pressure, which is towards N₂O₄(g). Additionally, decreasing the temperature will also favor the exothermic reaction, which produces more N₂O₄(g) molecules. To determine if the reaction is at equilibrium in a closed container, one can observe any changes in the concentrations or pressure over time. If the concentrations and pressure remain constant over time, then the reaction has reached equilibrium.

Question 4

Activated complexes are

Accepted Answer

Activated complexes are high-energy species that are formed during a reaction and have a short lifespan before they either stabilize into products or dissociate back into reactants. They are a critical part of the reaction pathway as they represent the highest energy point that is needed to transition from reactants to products.

Question 5

Consider the following reaction carried out in a sealed container: 2SO₃(g)⇌ 2SO₂(g)+ O₂(g)A state of equilibrium cannot be reached if the container initially contains

Accepted Answer

For a reaction to reach equilibrium, there must be a possibility for both the forward and reverse reactions to occur. If the container only contains $O_2$, the reverse reaction cannot proceed because there are no products ($SO_3$ or $SO_2$) to convert back into reactants.

Question 6

For the reaction, CoO(s)+ H₂(g)⇌ Co(s)+ H₂O(g), at 550°C, the value of the equilibrium constant, K, is 67. The equilibrium constant expression is

Accepted Answer

The answer of For the reaction, CoO(s)+ H₂(g)⇌ Co(s)+ H₂O(g),...

Question 7

Identify the catalyst in the following three-step reaction. NO(g)+ O₂(g)→ NO₃(g)NO₃(g)+ NO(g)→ 2NO₂(g)NO₂(g)+ SO₂(g)→ NO(g)+ SO₃(g)

Accepted Answer

NO(g) is consumed in the first step and regenerated in the last step, indicating it acts as a catalyst.

Question 8

Consider the following reaction carried out in a sealed container: N₂(g)+ 3H₂(g)⇌ 2NH₃(g)A state of equilibrium cannot be reached if the container initially contains

Accepted Answer

Equilibrium can be reached from any starting mixture of reactants and products, except when only products are present and the reaction is irreversible. In this case, starting with only $NH_3$ (product) would not allow the reverse reaction to occur if the reaction is irreversible, hence no equilibrium can be established.

Question 9

In order to write the equilibrium constant expression for a reaction, you must

Accepted Answer

To write the equilibrium constant expression, we need the balanced chemical equation for the reaction. The other information such as mechanism, rate, and conditions may be necessary to calculate the equilibrium constant but are not required to write the expression itself. The concentrations of reactants and products are used to calculate the value of the equilibrium constant, but they are not essential to writing the expression.

Question 10

Select the correct equilibrium constant expression for the following reaction: H₂(g)+ I₂(g)⇌ 2HI(g)

Accepted Answer

The answer of Select the correct equilibrium constant expression for...

Question 11

Consider the following reaction at equilibrium at a given temperature: 2NH₃(g)+ heat ⇌ N₂(g)+ 3H₂(g)Which of the following will cause the value of the equilibrium constant for this process to change?

Accepted Answer

According to Le Chatelier's principle, increasing the temperature of an equilibrium system favors the endothermic reaction, which in this case is the forward reaction (since heat is a product in the forward reaction). Therefore, raising the temperature will shift the equilibrium towards the products, leading to an increase in the value of the equilibrium constant. The other choices will not have a significant effect on the equilibrium constant. Adding more reactants (choice A) will shift the equilibrium towards the products temporarily, but the system will eventually reestablish equilibrium. Increasing the pressure (choice B) will only have an effect if the number of moles of gas changes, which is not the case here. Adding a catalyst (choice C) will increase the rate of both the forward and reverse reactions, but will not affect the position of equilibrium or the value of the equilibrium constant. Adding neon to the system (choice E) is essentially adding an inert gas, which will not participate in the reaction and will not affect the equilibrium constant.

Question 12

Select the correct equilibrium constant expression for the reaction: CH₄(g)+ 2H₂S(g)⇌ CS₂(g)+ 4H₂(g)

Accepted Answer

The answer of Select the correct equilibrium constant expression for...

Question 13

What is the balanced chemical equation that corresponds to the equilibrium constant expression (assuming a homogeneous equilibrium in the gas state)?

Accepted Answer

The answer of What is the balanced chemical equation that...

Question 14

What is the balanced chemical equation that corresponds to the equilibrium constant expression (assuming a homogeneous equilibrium in the gas state)?

Accepted Answer

The equilibrium constant expression for this reaction is Kc = [C]^2/([A][B]), which indicates that the stoichiometric coefficients of A and B must be 1, while that of C must be 2. Thus, option D is the only balanced chemical equation that satisfies this condition.

Question 15

What is the balanced chemical equation that corresponds to the equilibrium constant expression (assuming a homogeneous equilibrium in the gas state)?

Accepted Answer

The answer of What is the balanced chemical equation that...

Question 16

Consider the following reaction carried out in a sealed container: N₂(g)+ 3H₂(g)⇌ 2NH₃(g)A state of equilibrium can be reached if the container initially contains

Accepted Answer

Equilibrium can be established from any combination of reactants and products, as the system will adjust itself to reach the equilibrium state regardless of the starting materials.

Question 17

Given that evaporation is an endothermic process, which of the following sets of changes would cause the following system at equilibrium to shift to increase the number of I₂ molecules in the gas phase? I₂(s)⇌ I₂(g)

Accepted Answer

According to Le Chatelier's principle, increasing the temperature will shift the equilibrium to the side of the reaction that absorbs heat, which in this case is the endothermic process of evaporation. Additionally, increasing the volume will also favor the side with more moles of gas, which in this case is the gas phase. Therefore, increasing the container volume and increasing the temperature will cause the system to shift to the right, increasing the number of I₂ molecules in the gas phase.

Question 18

Select the correct equilibrium constant expression for the reaction 4NH₃(g)+ 3O₂(g)⇌ 2N₂(g)+ 6H₂O(g)

Accepted Answer

The answer of Select the correct equilibrium constant expression for...

Question 19

Consider the following reaction carried out in a sealed container: 2SO₃(g)⇌ 2SO₂(g)+ O₂(g)A state of equilibrium can be reached if the container initially contains

Accepted Answer

Equilibrium can be established from any starting mixture of reactants and products in a closed system, as the reaction can proceed in either direction to reach equilibrium.

Question 20

The graph shows the change in concentrations of the reactant and product as a reaction proceeds. At what point is equilibrium first reached?

Accepted Answer

The answer of The graph shows the change in concentrations...

Quiz 12: Reaction Rates and Chemical Equilibrium

When a chemical system has reached equilibrium

Identify the catalyst in the following three-step process for the decomposition of ozone. O₃(g) ⇌ O₂(g) + O(g) NO(g) + O₃(g) → NO₂(g) + O₂(g) O(g) + NO₂(g) → O₂(g) + NO(g)

Activated complexes are

Consider the following reaction carried out in a sealed container: 2SO₃(g) ⇌ 2SO₂(g) + O₂(g) A state of equilibrium cannot be reached if the container initially contains

For the reaction, CoO(s) + H₂(g) ⇌ Co(s) + H₂O(g) , at 550°C, the value of the equilibrium constant, K, is 67. The equilibrium constant expression is

Identify the catalyst in the following three-step reaction. NO(g) + O₂(g) → NO₃(g) NO₃(g) + NO(g) → 2NO₂(g) NO₂(g) + SO₂(g) → NO(g) + SO₃(g)

Consider the following reaction carried out in a sealed container: N₂(g) + 3H₂(g) ⇌ 2NH₃(g) A state of equilibrium cannot be reached if the container initially contains

In order to write the equilibrium constant expression for a reaction, you must

Select the correct equilibrium constant expression for the following reaction: H₂(g) + I₂(g) ⇌ 2HI(g)

Consider the following reaction at equilibrium at a given temperature: 2NH₃(g) + heat ⇌ N₂(g) + 3H₂(g) Which of the following will cause the value of the equilibrium constant for this process to change?

Select the correct equilibrium constant expression for the reaction: CH₄(g) + 2H₂S(g) ⇌ CS₂(g) + 4H₂(g)

What is the balanced chemical equation that corresponds to the equilibrium constant expression (assuming a homogeneous equilibrium in the gas state) ?

What is the balanced chemical equation that corresponds to the equilibrium constant expression (assuming a homogeneous equilibrium in the gas state) ?

What is the balanced chemical equation that corresponds to the equilibrium constant expression (assuming a homogeneous equilibrium in the gas state) ?

Consider the following reaction carried out in a sealed container: N₂(g) + 3H₂(g) ⇌ 2NH₃(g) A state of equilibrium can be reached if the container initially contains

Given that evaporation is an endothermic process, which of the following sets of changes would cause the following system at equilibrium to shift to increase the number of I₂ molecules in the gas phase? I₂(s) ⇌ I₂(g)

Select the correct equilibrium constant expression for the reaction 4NH₃(g) + 3O₂(g) ⇌ 2N₂(g) + 6H₂O(g)

Consider the following reaction carried out in a sealed container: 2SO₃(g) ⇌ 2SO₂(g) + O₂(g) A state of equilibrium can be reached if the container initially contains

The graph shows the change in concentrations of the reactant and product as a reaction proceeds. At what point is equilibrium first reached?

Quiz 12: Reaction Rates and Chemical Equilibrium

When a chemical system has reached equilibrium

Identify the catalyst in the following three-step process for the decomposition of ozone. O3(g) ⇌ O2(g) + O(g) NO(g) + O3(g) → NO2(g) + O2(g) O(g) + NO2(g) → O2(g) + NO(g)

Activated complexes are

Consider the following reaction carried out in a sealed container: 2SO3(g) ⇌ 2SO2(g) + O2(g) A state of equilibrium cannot be reached if the container initially contains

For the reaction, CoO(s) + H2(g) ⇌ Co(s) + H2O(g) , at 550°C, the value of the equilibrium constant, K, is 67. The equilibrium constant expression is

Identify the catalyst in the following three-step reaction. NO(g) + O2(g) → NO3(g) NO3(g) + NO(g) → 2NO2(g) NO2(g) + SO2(g) → NO(g) + SO3(g)

Consider the following reaction carried out in a sealed container: N2(g) + 3H2(g) ⇌ 2NH3(g) A state of equilibrium cannot be reached if the container initially contains

In order to write the equilibrium constant expression for a reaction, you must

Select the correct equilibrium constant expression for the following reaction: H2(g) + I2(g) ⇌ 2HI(g)

Consider the following reaction at equilibrium at a given temperature: 2NH3(g) + heat ⇌ N2(g) + 3H2(g) Which of the following will cause the value of the equilibrium constant for this process to change?

Select the correct equilibrium constant expression for the reaction: CH4(g) + 2H2S(g) ⇌ CS2(g) + 4H2(g)

What is the balanced chemical equation that corresponds to the equilibrium constant expression (assuming a homogeneous equilibrium in the gas state) ?

What is the balanced chemical equation that corresponds to the equilibrium constant expression (assuming a homogeneous equilibrium in the gas state) ?

What is the balanced chemical equation that corresponds to the equilibrium constant expression (assuming a homogeneous equilibrium in the gas state) ?

Consider the following reaction carried out in a sealed container: N2(g) + 3H2(g) ⇌ 2NH3(g) A state of equilibrium can be reached if the container initially contains

Given that evaporation is an endothermic process, which of the following sets of changes would cause the following system at equilibrium to shift to increase the number of I2 molecules in the gas phase? I2(s) ⇌ I2(g)

Select the correct equilibrium constant expression for the reaction 4NH3(g) + 3O2(g) ⇌ 2N2(g) + 6H2O(g)

Consider the following reaction carried out in a sealed container: 2SO3(g) ⇌ 2SO2(g) + O2(g) A state of equilibrium can be reached if the container initially contains

The graph shows the change in concentrations of the reactant and product as a reaction proceeds. At what point is equilibrium first reached?

Identify the catalyst in the following three-step process for the decomposition of ozone. O₃(g) ⇌ O₂(g) + O(g) NO(g) + O₃(g) → NO₂(g) + O₂(g) O(g) + NO₂(g) → O₂(g) + NO(g)

Consider the following reaction carried out in a sealed container: 2SO₃(g) ⇌ 2SO₂(g) + O₂(g) A state of equilibrium cannot be reached if the container initially contains

For the reaction, CoO(s) + H₂(g) ⇌ Co(s) + H₂O(g) , at 550°C, the value of the equilibrium constant, K, is 67. The equilibrium constant expression is

Identify the catalyst in the following three-step reaction. NO(g) + O₂(g) → NO₃(g) NO₃(g) + NO(g) → 2NO₂(g) NO₂(g) + SO₂(g) → NO(g) + SO₃(g)

Consider the following reaction carried out in a sealed container: N₂(g) + 3H₂(g) ⇌ 2NH₃(g) A state of equilibrium cannot be reached if the container initially contains

Select the correct equilibrium constant expression for the following reaction: H₂(g) + I₂(g) ⇌ 2HI(g)

Consider the following reaction at equilibrium at a given temperature: 2NH₃(g) + heat ⇌ N₂(g) + 3H₂(g) Which of the following will cause the value of the equilibrium constant for this process to change?

Select the correct equilibrium constant expression for the reaction: CH₄(g) + 2H₂S(g) ⇌ CS₂(g) + 4H₂(g)

Consider the following reaction carried out in a sealed container: N₂(g) + 3H₂(g) ⇌ 2NH₃(g) A state of equilibrium can be reached if the container initially contains

Given that evaporation is an endothermic process, which of the following sets of changes would cause the following system at equilibrium to shift to increase the number of I₂ molecules in the gas phase? I₂(s) ⇌ I₂(g)

Select the correct equilibrium constant expression for the reaction 4NH₃(g) + 3O₂(g) ⇌ 2N₂(g) + 6H₂O(g)

Consider the following reaction carried out in a sealed container: 2SO₃(g) ⇌ 2SO₂(g) + O₂(g) A state of equilibrium can be reached if the container initially contains