Chemical Equilibrium Part 2 Module Question #27

[Nancy 1B]

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 please help work through this problem, I'm not sure how to go about solving it. Thanks!

[Seth_Evasco1L]

1. Create an ICE table for the reaction.
2. Find the molarity for H₂O since it gives you the value in moles. (No need to find the molarity for C because it's a solid and is not involved in the equilibrium constant)
3. The initial concentration for CO and H₂ is going to be 0.
4. You know the equilibrium concentration for H₂ is 0.040 M which means the change is 0.040 M.
5. You subtract that change from the initial concentration to get the equilibrium concentration of H₂O.

[Christy Zhao 1H]

Adding on, you should get 0.05 M H2O for the initial concentration, and you know x=0.040 from H2. The equilibrium concentration for H2O is 0.05-x, and plugging in x you would get 0.01 M H2O.