# Need help with equilibrium equations - Please

1. Jul 29, 2013

### aaronfue

Need help with equilibrium equations -- ASAP Please

1. The problem statement, all variables and given/known data

I'm studying for a final that I'm taking tomorrow and am stuck on the following:

Calculate Kc for the reaction:

4NOBr (g) $\Leftrightarrow$ 4NO (g) + 2Br2 (g)

given the following information:

2NO(g) + Br2 (g) $\Leftrightarrow$ 2NOBr (g); K = 2.0

2. Relevant equations

Not sure about which equations other than Kc = $\frac{[products]}{[reactions]}$

3. The attempt at a solution

I can't even start this answer. My first assumption of where to start was to write the second equation backwards, just so it looked like the first!!??

2. Jul 30, 2013

### epenguin

3. Jul 30, 2013

### janhaa

$$K_c=(1/K)^2$$