Question

For the following reaction, find the value of Q and predict the direction of change, given that a 1L flask initially contains 2 moles S8, 2 moles SF6, and 2 moles F2.

1/8 S8 (s) + 3 F2 (g) ⇄ SF6 (g) Kc = 0.425

(A) Q = K, system is at equilibrium
(B) Q < K, reaction will make more reactants
(C) Q < K, reaction will make more products
(D) Q > K, reaction will make more reactants
(E) Q > K, reaction will make more products

Answer 1

To find the direction of the reaction, calculate the reaction quotient (Q) by using the initial molar concentrations of reactants and products, then compare Q to the equilibrium constant (Kc). In this case, Q is less than Kc, so the reaction will proceed to the right to form more products. So the correct option is C.

Step-by-step explanation:

To determine the direction of the reaction for 1/8 S8 (s) + 3 F2 (g) ⇌ SF6 (g) with a given equilibrium constant (Kc) of 0.425, we need to calculate the reaction quotient (Q) and compare it to Kc.

First, calculate the initial molar concentrations:

• [S8] = (2 moles S8)/(1 L) = 2 M (since S8 is a solid, its concentration does not affect Q)
• [SF6] = (2 moles SF6)/(1 L) = 2 M
• [F2] = (2 moles F2)/(1 L) = 2 M

Next, we apply the reaction quotient equation, Q = [SF6]/[F2]3. Substituting the initial concentrations:

Q = (2)/(2)3 = 0.25

Comparing Q to Kc:

Q (0.25) < Kc (0.425), indicating that the reaction will proceed to the right, forming more products (SF6), until equilibrium is reached. Therefore, the answer is (C) Q < K, the reaction will make more products.

Answer 2

C) Q < K, reaction will make more products

Step-by-step explanation:

• 1/8 S8(s) + 3 F2(g) ↔ SF6(g)

∴ Kc = 0.425 = [ SF6 ] / [ F2 ]³

∴ Q = [ SF6 ] / [ F2 ]³

∴ [ SF6 ] = 2 mol/L

∴ [ F2 ] = 2 mol/L

⇒ Q = ( 2 ) / ( 2³)

⇒ Q = 0.25

⇒ Q < K, reaction will make more products