chem-3-revision2

If Q < K for a reaction mixture, what will happen?

The reaction will shift toward the products.

The reaction has gone to completion.

The system is already at equilibrium.

The reaction will shift toward the reactants.

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The equilibrium constant (Kc) provides information about:

The extent to which a reaction is growing

The initial concentration of reactants and products.

The rate at which equilibrium is reached.

The ratio of product to reactant concentrations at equilibrium.

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The equilibrium constant expression does not include pure solids or liquids because:

Their concentrations remain constant.

They are not part of chemical reactions.

They do not affect equilibrium shifts.

They are always present in excess.

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What happens to the value of Q as a reaction progresses toward equilibrium?

It becomes zero.

It remains constant.

It always increases.

It changes until it equals Kc.

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Which of the following statements about the reaction quotient (Q) are true?

Q is only defined at equilibrium.

If Q > K, the reaction shifts toward the products.

If Q < K, the reaction shifts toward the reactants.

When Q = K, the reaction is at equilibrium.

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For a given reaction, the equilibrium expression is written with:

Reactants in the denominator and products in the numerator.

Products in the denominator and reactants in the numerator.

All species summed together.

The initial concentrations of all species.

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In the equilibrium expression Kc = [C]ᶜ[D]ᵈ / [A]ᵃ[B]ᵇ, what do the exponents (a, b, c, d) represent?

The partial pressures of gases in the system.

The number of molecules present in the reaction.

The coefficients of the balanced chemical equation.

The experimental rate law exponents.

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The equilibrium position of a reaction depends on:

The initial concentration of reactants only.

The activation energy of the reaction.

The magnitude of the equilibrium constant (Kc).

The speed of the forward reaction only.

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For the reaction CH₄(g) + H₂O(g) ⇌ CO(g) + 3H₂(g), which of the following is the correct Kc expression?

Kc = [CH₄][H₂O] / [CO][H₂]³

Kc = [CO][H₂]³ / [CH₄][H₂O]

Kc = [CO][3H]2 / [CH₄][H₂O]

Kc = [CO][H₂] / [CH₄][H₂O]³

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10.

Which of the following statements is true regarding equilibrium?

Adding a catalyst will change the equilibrium constant.

A reaction at equilibrium will not shift unless an external change is imposed.

At equilibrium, the concentration of reactants is always higher than products.

The value of Kc changes when reactant concentrations are altered.

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