[Missy]

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

When one mole of methane reacts according to the given equation, 206.1 kJ of energy is absorbed. Write a thermochemical equation for one mole of methane in the given reaction. Also write an equation with notation for the reverse reaction for one mole of methane.

It would be great if someone could go through this question for me please. I have spent a lot of time on it and an not quite understanding how to find Q. I am particularly having trouble with the last part of the question that is asking for the equation for the reverse reaction.

Thanks!

[cliverlong]

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

When one mole of methane reacts according to the given equation, 206.1 kJ of energy is absorbed. Write a thermochemical equation for one mole of methane in the given reaction. Also write an equation with notation for the reverse reaction for one mole of methane.

It would be great if someone could go through this question for me please. I have spent a lot of time on it and an not quite understanding how to find Q. I am particularly having trouble with the last part of the question that is asking for the equation for the reverse reaction.

Thanks!

This is the steam-reforming reaction.

Quoting from the Doc Brown website

These days hydrogen is primarily made by reacting methane (natural gas) and water (steam), and the process is called steam-methane reforming.

CH₄(g) + H₂O(g)  3H₂(g) + CO(g) (ΔH = +206 kJ mol^-1)

The term: ΔH = +206 kJ mol^-1 means energy (enthalpy strictly) needs to be put into the reaction for it to complete. That is the meaning of the "absorbed" in your question. a positive value for ΔH means causes the reaction to be classified as endothermic.

To work out the reverse you use Hess' Law in simple form. The reverse of a reaction undergoes the same enthalpy change as the forward reaciton but with the opposite sign.

Clive