The Reaction Quotient Video Lessons

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Problem: Given that Kp = 1.39 at 400°C for the reaction, P4(g) <=> 2 P2(g), which answer best describes the reaction when 1.50 mol of P4(g) and 1.15 mol of P2(g) are mixed in a 25.0 L, closed container at 400°C? [REMEMBER: it’s Kp] a. Qp = 1.95, the reaction proceeds to the left.b. Qp = 1.95, the reaction proceeds to the right.c. Qp = 0.51, the reaction proceeds to the left.d. Qp = 0.51, the reaction proceeds to the right.e. Qp = 0.77, the reaction proceeds to the left.

FREE Expert Solution

We’re being asked to determine what happens to the reaction when 1.50 mol of P4(g) and 1.15 mol of P2(g) are mixed in a 25.0 L closed container at 400 °C.

P4(g) ⇌ 2 P2(g);            Kp = 1.39 

We will use the reaction quotient, Q, to determine if a chemical reaction would be at equilibrium or not. The formula for Q is:

Q=productsreactants

Depending on if Q is greater than or less than K our reaction will shift to attain equilibrium by reaching the equilibrium constant K:

If Q = K           → the reaction is at equilibrium
If Q < K           → the reaction shifts in the forward direction to reach equilibrium
If Q > K           → the reaction shifts in the reverse direction to reach equilibrium


Since the Kp is given, we need to calculate the pressure of each gas first using the ideal gas equation:

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Problem Details

Given that Kp = 1.39 at 400°C for the reaction, P4(g) <=> 2 P2(g), which answer best describes the reaction when 1.50 mol of P4(g) and 1.15 mol of P2(g) are mixed in a 25.0 L, closed container at 400°C? [REMEMBER: it’s Kp

a. Qp = 1.95, the reaction proceeds to the left.
b. Qp = 1.95, the reaction proceeds to the right.
c. Qp = 0.51, the reaction proceeds to the left.
d. Qp = 0.51, the reaction proceeds to the right.
e. Qp = 0.77, the reaction proceeds to the left.

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