CH4(g) + H2O(g)3H2(g) + CO(g)

Question

A scientist measures the standard enthalpy change for the following reaction to be 201.6 kJ:

CH₄(g) + H₂O(g)3H₂(g) + CO(g)

Based on this value and the standard enthalpies of formation for the other substances, the standard enthalpy of formation of CO(g) is  kJ/mol.

Answer 1

You should look up the ∆Hº_f for H₂(g) which will be zero, and also for CH₄(g) and H₂O(g). Then use the fact that ∆Hºrxn = ∑∆Hº_f products - ∑∆Hº_f reactants

201.6 kJ = ∆Hº_f CO(g) - [∆Hº_fCH4(g) + ∆Hº_fH₂O(g)] and solve for ∆Hº_f CO(g)