# Considering H2(g) + I2(g) â†” 2HI and a temperature of 731K; 2.40 mol of H2 and 2.40 mol of I2 are placed in a 1.00 L vessel. What is the equilibrium concentration of H2 in the gaseous mixture? The equilibrium constant is K = 49.0

##### 1 Answer

The answer is

Starting from the balanced chemical equation

Since the reaction's equlibrium constant,

From the data given we can determine the starting concentrations of both

We can now determine the equilibrium concentrations for this reaction by using the ICE method (more here: http://en.wikipedia.org/wiki/RICE_chart)

...

**I**: 2.40........2.40...........0

**C**: (-x).............(-x)..........(+2x)

**E**: 2.40-x.....2.40-x........2x

We know that

Rearranging this equation will give us

Therefore,

Notice how the final concentrations match the estimate derived from

A quick word on the ICE table...the starting concentration of **0 M** because only **x** simply represents the change in concentrations in accordance to the balanced chemical equation -> 1 mole of