Question

Consider the following reaction and its corresponding equilibrium constant to answer the next two questions:

P₄ (g) + 6 H₂ (g) Û 4 PH₃ (g) K_p = 6.48 x 10^-6 (at 25 ^oC)

17. What is the value of K_c for the following reaction given that K_p equals 6.48 x 10^-6 (at 25 ^oC)?

a) K_c = 3.98 x 10^-12 b) K_c = 4.42 x 10^-10 c) K_c = 5.60 x 10^-5

d) K_c = 9.49 x 10^-2 e) K_c = 9.848 x 10⁴

18. Given the reaction above and it’s corresponding equilibrium constant, what is the value of the equilibrium constant defined below?

2 PH₃ (g) Û ½ P₄ (g) + 3 H₂ (g) K_net = ??

a) K_net = 4.20 x 10^-11 b) K_net = 2.55 x 10^-3 c) K_net = 3.93 x 10²

d) K_net = 1.54 x 10⁵ e) K_net = 2.38 x 10¹⁰

^{I understand how to get number 17. I need help with 18.}