Module 2 Question 27

[Haley Dveirin 1E]

27. A mixture of 2.5 moles H2O and 100 g of C are placed in a 50 L container and allowed to come to equilibrium subject to the following reaction:
C(s) + H2O (g) ⇌ CO (g) + H2 (g)
The equilibrium concentration of hydrogen is found to be [H2] = 0.040 M. What is the equilibrium concentration of water, [H2O]?

Can someone explain how to solve this and the answer?

[Paige Lee 1A]

100g of C is 8.326 moles of C
Set up an ICE table

Initial C: 8.326/50 = 0.16652
Initial H2O: 2.5/50 = 0.05
Initial CO: 0
Initial H2: 0

Change: -x for C and H2O, +x for CO and H2

Equilibrium C: 0.16652-x
Equilibrium H2O: 0.05-x
Equilibrium CO and H2: both are x, which is given to be 0.04

Plug x=0.04 into H2O=0.05-x, and get that [H2O] = 0.01M