Question

A major industrial source of hydrogen gas is by the following reaction: CH₄(g) + H₂O(g) → CO(g) + 3 H₂(g). Use bond energies to predict ΔH (in kJ) for this reaction.

a) -150 kJ
b) -300 kJ
c) -450 kJ
d) -600 kJ

Answer 1

To find the enthalpy change (ΔH) for the given reaction, bond energies of the reactants and products are summed, with energies for bonds broken subtracted by energies for bonds formed. Without the exact bond energies provided, the value of ΔH cannot be computed.

Step-by-step explanation:

To predict the enthalpy change (ΔH) for the reaction CH4(g) + H2O(g) → CO(g) + 3 H2(g), we can use bond energies. The calculation involves summing the bond energies for all the bonds broken minus the bond energies for all the bonds formed in the reaction.

The bond energies needed for this calculation are typically given in a table, but as they are not supplied here, let's assume you have them. You would calculate as follows:

1. Add together the energy required to break one mole of C-H bonds in CH4 and the energy required to break one mole of O-H bonds in H2O.
2. Subtract the energy released from forming one mole of C=O bonds in CO and three moles of H-H bonds in H2.
3. The result will give you the approximate ΔH for the reaction.

Without the exact bond energies, we cannot compute the actual value, so we cannot select the correct option from a), b), c), d).