# Homework Help: Proving Kp will remain constant if total press. is doubled

1. Mar 9, 2015

### CroSinus

1. The problem statement, all variables and given/known data
Is there a way I can prove (mathematically) that Kp for the chemical reaction: H2(g) + I2(s) <--> 2HI(g) will remain constant if I double the total pressure of the mixture?

2. Relevant equations
H2(g) + I2(s) <--> 2HI(g)

3. The attempt at a solution
If I write the expression for Kp from the above reaction I get: Kp = p^2(HI) / p(H2). Now, if I double the total pressure of the mixture I get K'p = 2Kp. However, I know from the theory that Kp is independent of the total pressure of the mixture. But is there a way I can prove it mathematically? Thanks in advance for your help.

2. Mar 10, 2015

### Bystander

It appears that you're trying to preserve the degree of completion rather than Kp as a function of pressure. Remember that Kp is in terms of partial pressures.

3. Mar 10, 2015

### Staff: Mentor

That Kp is a constant can be only proved experimentally, not mathematically.