Homework 11.7c

[Courtnie Ly]

c) Assuming that the initial pressure of X2 was 0.10 bar, calculate the value of K for the decomposition.

When calculating K, only given the initial pressure of X2, why can you use the molar ratio to find the pressure of the products as well? Is it because pressure remains constant throughout the system/reaction? Also, when plugging in the value for P(X2), why would you do (5/17) x 0.1 rather than just 0.1?

[Amy Pai]

1). If you rearrange the ideal gas law, u get V1/V2= n1/n2, meaning that the volume ratio of two gases at the same temperature and pressure is equal to their molar ratio.

2). You do 5/12 because that's the number of X2s in equilibrium. 0.1 bar gives you the total initial pressure of the system, so I think they multiplied by 0.1 for the final Kp value.