Kc = 1.88 for 2HI(g) ↔ H2(g) + I2(g)

[Madelin Pierce]

Homework Statement

Kc = 1.37 for HI(g) ↔ 1/2 H2(g) + 1/2 I2(g). What is Kc (to 3 decimal places) for H2(g) + I2(g) ↔ 2HI(g)?

Homework Equations

Kc= Products/Reactants, Ice Tables

The Attempt at a Solution

I tried an ice table, but I’m not sure what to do with the Kc value I’m given when I have to another Kc value

 

[Wrichik Basu]

$$K_{c_1} = 1.37 = \dfrac{[H_2]^{1/2} [I_2]^{1/2}}{[HI]}$$ and $$K_{c_2} = \dfrac{[HI]^2}{[H_2][I_2]}$$ Can you find a relation between $K_{c_1}$ and $K_{c_2}$?

 

[Madelin Pierce]

I know the reaction reversed and doubled. But I don’t know how to solve for Kc mathematically with this set-up.

 

[Wrichik Basu]

But I don’t know how to solve for Kc mathematically with this set-up.

What maths are you referring to? If you can find $K_{c_2}$ in terms of $K_{c_1}$, then can't you find $K_{c_2}$?

 

[Chestermiller]

I know the reaction reversed and doubled. But I don’t know how to solve for Kc mathematically with this set-up.

What do you get if you square @Wrichik Basu's first equation, and then multiply it by his second equation.