Answer to Question #118911 in Chemistry for Amanda G

Question

CH4+2H2O+heat <--> CO2+4H2

A test reaction is done starting with only methane and excess water in the autoclave. If the initial concentration of methane is 0.112 mol/L, and the methane concentration at equilibrium is 0.017 mol / L, then the equilibrium concentration of hydrogen is?
(two digit answer)

Answer 1

According to the reaction equation:

CH₄+2H₂O+heat $\rightarrow$ CO₂+4H₂,

1 mol of methane produces 4 moles of hydrogen. The concentration of methane decreased by 0.112 - 0.017 = 0.095 M. As the initial concentration of hydrogen in the autoclave is zero, the concentration of hydrogen at the equilibrium is :

$[H_2] = 0+ 4(c_{CH_4}^0 - [CH_4]) = 4·0.095=0.38$ M.

Answer: the equilibrium concentration of hydrogen is 0.38 M.