Chemistry Test Chemical Equilibrium

Question 1

What is the correct definition of chemical equilibrium in a reversible reaction?

Accepted Answer

The rates of the forward and reverse reactions are equal

Answer

The reaction has stopped completely

Answer

The concentrations of reactants and products are equal

Answer

All reactants have been converted to products

Question 2

Which expression correctly represents the equilibrium constant Kc for the reaction: N₂(g) + 3H₂(g) ⇌ 2NH₃(g)?

Accepted Answer

Kc = [NH₃]² / ([N₂][H₂]³)

Answer

Kc = [N₂][H₂]³ / [NH₃]²

Answer

Kc = [NH₃] / ([N₂][H₂])

Answer

Kc = [N₂][H₂] / [NH₃]

Question 3

If Kc >> 1 for a reaction, what does this indicate about the equilibrium position?

Accepted Answer

The equilibrium strongly favors the products

Answer

The equilibrium strongly favors the reactants

Answer

Reactant and product concentrations are nearly equal

Answer

The reaction does not proceed in either direction

Question 4

For the reaction H₂(g) + I₂(g) ⇌ 2HI(g), if [H₂] = 0.5 M, [I₂] = 0.5 M, and [HI] = 2.0 M at equilibrium, what is Kc?

Accepted Answer

16

Answer

4

Answer

8

Answer

32

Question 5

What is the relationship between Kp and Kc for a gas-phase reaction?

Accepted Answer

Kp = Kc(RT)^Δn

Answer

Kp = Kc / (RT)

Answer

Kp = Kc + RT·Δn

Answer

Kp = Kc × Δn

Question 6

Which of the following does NOT affect the numerical value of the equilibrium constant Kc?

Accepted Answer

Adding a catalyst

Answer

Increasing the temperature

Answer

Reversing the chemical equation

Answer

Multiplying all coefficients by 2

Question 7

For the equilibrium: CaCO₃(s) ⇌ CaO(s) + CO₂(g), which expression correctly represents the equilibrium constant Kc?

Accepted Answer

Kc = [CO₂]

Answer

Kc = [CaO][CO₂] / [CaCO₃]

Answer

Kc = [CO₂] / [CaCO₃]

Answer

Kc = [CaCO₃] / ([CaO][CO₂])