If Kc = 0.600 and Kp = 359 for a hypothetical reaction, which of the following equations could represent the reaction at 25°C?

• A. A(g) + 2B(g) ⇌ C(g)
• B. A(g) ⇌ B(g) + C(g)
• C. 2A(g) ⇌ B(g) + 2C(g)
• D. 2A(g) + B(g) ⇌ 3C(g)

Answer: (D)

Verified step by step guidance

1. Understand the relationship between Kc and Kp. The equation that relates Kc and Kp is: $K{p}_{}=K{c}_{}\left(RT\right){∆}^n$, where Δn is the change in moles of gas (moles of gaseous products - moles of gaseous reactants), R is the ideal gas constant, and T is the temperature in Kelvin.
2. Calculate Δn for each reaction option. For example, for the reaction A(g) + 2B(g) ⇌ C(g), Δn = (1 - (1 + 2)) = -2.
3. Use the given Kc and Kp values to find the correct Δn. Rearrange the equation to solve for Δn: $∆n=\frac{\ln \left(\frac{K}{p_{}}\right)}{\ln \left(RT\right)}$.
4. Substitute the known values (Kc = 0.600, Kp = 359, R = 0.0821 L·atm/mol·K, T = 298 K) into the equation to find Δn.
5. Compare the calculated Δn with the Δn values for each reaction option to determine which reaction matches the given Kc and Kp values. The correct reaction will have a Δn that satisfies the equation with the given Kc and Kp.