Question 1

Consider the reaction CO(g) + H₂O(g) CO₂(g) + H₂(g), represented by the following diagram: What is the composition of this system when the reaction reaches equilibrium?

Accepted Answer

At equilibrium, the reaction will proceed in such a way that the concentrations of products and reactants will become constant. In this case, the law of mass action can be used to determine the equilibrium concentrations. The balanced equation for the reaction is: CO(g) + H₂O(g) ⇌ CO₂(g) + H₂(g) The equilibrium constant expression is: Kc = [CO₂][H₂] / [CO][H₂O] The initial concentrations are: [CO] = 3 mol [H₂O] = 3 mol [CO₂] = 0 mol [H₂] = 0 mol Substituting these values into the expression for Kc gives: Kc = (0 mol)(0 mol) / (3 mol)(3 mol) = 0 This implies that the concentration of products is zero at equilibrium. Therefore, all the reactants must be conserved. The composition of the system at equilibrium is: [CO] = 2 mol [H₂O] = 2 mol [CO₂] = 8 mol [H₂] = 8 mol Hence, the correct answer is C.

Question 2

Which of the following statements is correct for a reaction in which K_eq << 1?

Accepted Answer

K_eq << 1 means that the equilibrium constant is much smaller than 1, which indicates that the reaction heavily favors the reactants. Therefore, there are more reactants than products at equilibrium.

Question 3

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, when a system at equilibrium is subjected to a change, it will shift its position to counteract the change. Since evaporation is an endothermic process, increasing temperature will favor the forward reaction (evaporation), which means more I₂ molecules will move from the solid phase to the gas phase. Additionally, increasing the volume of the container will decrease the pressure, which would favor the side with more moles of gas. In this case, the forward reaction (evaporation) produces more gas molecules, so increasing the volume will shift the equilibrium to the products side, resulting in more I₂ molecules in the gas phase. Therefore, the best choice is A (Increasing container volume and increasing temperature).

Question 4

Which equilibrium constant represents a reaction that is reactant favored?

Accepted Answer

The equilibrium constant (K_eq) represents the ratio of the concentrations of the products to the concentrations of the reactants at equilibrium. A K_eq value less than 1 indicates that the equilibrium position lies to the left, favoring the reactants.

Question 5

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...

Question 6

The amount of energy that reactant molecules must possess in order to react is the activation energy.

Accepted Answer

This is true according to the definition of activation energy.

Question 7

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 reached from any starting combination of reactants and/or products as long as the system is closed and the reaction is reversible.

Question 8

A reaction that has a high activation energy will have a high rate of reaction.

Accepted Answer

A high activation energy means that it is difficult for the reactants to overcome the energy barrier and proceed with the reaction, leading to a lower rate of reaction.

Question 9

Which of the following statements is correct for a reaction in which K_eq >> 1?

Accepted Answer

The notation K_eq represents the equilibrium constant of the reaction, where K_{eq represents the concentration of products at equilibrium and} represents the concentration of reactants at equilibrium. When K_eq << 1, it means that the concentration of products is much lower than the concentration of reactants at equilibrium. Therefore, there are more reactants than products at equilibrium. This also indicates that the reverse reaction is favored over the forward reaction because the reactants are not being fully converted into products.

Question 10

Which equilibrium constant represents a reaction that is product favored?

Accepted Answer

An equilibrium constant (K_eq) greater than 1 indicates that the reaction is product favored, meaning the products are favored at equilibrium. K_eq = 6.3 x 10⁵ is much greater than 1, indicating a product-favored reaction.

Question 11

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, the system will shift in the direction that counteracts the change. Decreasing the container volume will increase the pressure, which will favor the side with fewer moles of gas. Since there are two moles of gas on the left side and only one mole on the right side, the system will shift to the right to increase the number of N₂O₄(g) molecules. Decreasing the temperature will also favor the exothermic reaction, which produces heat. An observation that indicates the reaction is at equilibrium in a closed container is the absence of any visible changes over time, such as a change in color or the formation of a precipitate. The concentrations of the reactants and products also remain constant at equilibrium.

Question 12

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 13

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 14

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 15

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

Accepted Answer

The equilibrium constant expression can be written solely based on the balanced chemical equation for the reaction. It does not require knowledge of the mechanism, rates, or specific conditions of the system. While knowing the concentrations of reactants and products can help calculate the numerical value of the equilibrium constant, it is not necessary for writing the expression itself.

Question 16

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 17

For a given reaction, which of the following statements can be made about the value of the equilibrium constant?

Accepted Answer

The equilibrium constant (Kc) depends on the temperature at which the reaction is taking place. The value of Kc changes with the change in temperature according to the equation -ΔH/R. Therefore, option D is the correct answer. Options A, B, C, and E are not true statements about the equilibrium constant.

Question 18

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 19

The high potential-energy chemical species that is produced when an effective collision occurs is called a catalyst.

Accepted Answer

The high potential-energy chemical species that is produced when an effective collision occurs is called an activated complex, not a catalyst. A catalyst is a substance that speeds up the rate of a chemical reaction without itself being consumed in the reaction.

Question 20

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.

Quiz 12: Reaction Rates and Chemical Equilibrium

Consider the reaction CO(g) + H₂O(g) CO₂(g) + H₂(g) , represented by the following diagram: What is the composition of this system when the reaction reaches equilibrium?

Which of the following statements is correct for a reaction in which K_eq << 1?

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)

Which equilibrium constant represents a reaction that is reactant favored?

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

The amount of energy that reactant molecules must possess in order to react is the activation energy.

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

A reaction that has a high activation energy will have a high rate of reaction.

Which of the following statements is correct for a reaction in which K_eq >> 1?

Which equilibrium constant represents a reaction that is product favored?

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)

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

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

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

For a given reaction, which of the following statements can be made about the value of the equilibrium constant?

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 high potential-energy chemical species that is produced when an effective collision occurs is called a catalyst.

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

Quiz 12: Reaction Rates and Chemical Equilibrium

Consider the reaction CO(g) + H2O(g) CO2(g) + H2(g) , represented by the following diagram: What is the composition of this system when the reaction reaches equilibrium?

Which of the following statements is correct for a reaction in which Keq << 1?

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)

Which equilibrium constant represents a reaction that is reactant favored?

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

The amount of energy that reactant molecules must possess in order to react is the activation energy.

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

A reaction that has a high activation energy will have a high rate of reaction.

Which of the following statements is correct for a reaction in which Keq >> 1?

Which equilibrium constant represents a reaction that is product favored?

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?

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)

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

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

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

For a given reaction, which of the following statements can be made about the value of the equilibrium constant?

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 high potential-energy chemical species that is produced when an effective collision occurs is called a catalyst.

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

Consider the reaction CO(g) + H₂O(g) CO₂(g) + H₂(g) , represented by the following diagram: What is the composition of this system when the reaction reaches equilibrium?

Which of the following statements is correct for a reaction in which K_eq << 1?

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)

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

Which of the following statements is correct for a reaction in which K_eq >> 1?

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)

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

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: 2SO₃(g) ⇌ 2SO₂(g) + O₂(g) A state of equilibrium can be reached if the container initially contains

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