Reaction Quotient, Q and Equilibrium Constant, K

Which of the following is true about chemical reaction at equilibrium

• only the forward reaction stops

• only the reverse reaction stops

• both forward and reverse reactions stop

• the rate constants for the forward and reverse reactions are equal

• the rates of the forward and reverse reactions are equal

Tags

NGSS.HS-PS1-6

How is the reaction quotient used to determine whether a system is at equilibrium?

• At equilibrium, the reaction quotient is undefined.

• The reaction is at equilibrium when Q < K.

• The reaction is at equilibrium when Q > K.

• The reaction is at equilibrium when Q = K.

Tags

NGSS.HS-PS1-6

If the reaction quotient Q has a smaller value than the related equilibrium constant, K, _________

• the reaction is at equilibrium

• the reaction is not at equilibrium, and will make more products at the expense of the reactants

• the reaction is not at equilibrium, and will make more reactants at the expense of the products

• the value of K will not increase until it is equal to Q

Tags

NGSS.HS-PS1-7

If the reaction quotient Q has a value larger than the related equilibrium constant, K _________

• the reaction is at equilibrium

• the reaction is not at equilibrium, and will make more products at the expense of reactants

• the reaction is not at equilibrium, and will make more reactants at the expense of products

• the value of K will increase until it is equal to Q

The value of the equilibrium constant, K_p for the reaction below is 3.1 × 10^-4 at 700K.

N₂ (g) + 3H₂ (g) ↔ 2NH₃ (g)

Given the initial partial pressure of the gases, P_N2 = 0.411 atm; P_H2 = 0.903 atm; P_NH3 = 0.224 atm, calculate the value of the reaction quotient, Q.

• Q = 0.0437

• Q = 0.1658

• Q = 0.6036

• Q = 0.1352

Tags

NGSS.HS-PS1-7

The value of the equilibrium constant, K_p for the reaction below is 3.1 × 10^-4 at 700K.

N₂ (g) + 3H₂ (g) ↔ 2NH₃ (g)

Given the initial partial pressure of the gases, P_N2 = 0.411 atm; P_H2 = 0.903 atm; P_NH3 = 0.224 atm. Predict the direction in which the reaction will proceed at 700 K.

• Since Q > K_p, the equilibrium will proceed to the left to bring the value Q down to 3.1 × 10^-4.

• Since Q > K_p, the equilibrium will proceed to the right to bring the value Q down to 3.1 × 10^-4.

• Since Q > K_p, the equilibrium will proceed to the left to bring the value Q up to 3.1 × 10^-4.

• Since Q > K_p, the equilibrium will proceed to the right to bring the value Q up to 3.1 × 10^-4.

For the reaction system:

2HI (g) ↔ H₂ (g) + I₂ (g)

K_c = 0.020 at 720 K

If the initial concentrations of HI, H₂ and I₂ are all 1.50 × 10^-3 M at 720 K, which one of the following statements is correct?

• The system is at equilibrium.

• The concentrations of HI and I₂ will increase as the system is approaching equilibrium.

• The concentration of HI will increase as the system is approaching equilibrium.

• The concentration of H₂ and I₂ will increase as the system is approaching equilibrium.

Tags

NGSS.HS-PS1-5

For the reaction, N₂O₄ (g) ↔ 2NO₂ (g), K_c = 0.21 at 100^oC. At initial, the [N₂O₄] = 0.12 M and [NO₂] = 0.55 M. Is the reaction at equilibrium? If not, in which direction it is progressing?

• Yes, the reaction is at equilibrium.

• No, the reaction is not at equilibrium. Q_c < K_c, therefore the reaction will proceed from left to right until Q_c = K_c.

• No, the reaction is not at equilibrium. Q_c > K_c, therefore the reaction will proceed from right to left until Q_c = K_c.

• No, the reaction is not at equilibrium. Q_c < K_c, therefore the reaction will proceed from right to left until Q_c = K_c.

Tags

NGSS.HS-PS1-5

NGSS.HS-PS1-6