$1)$ Hydrogen is a possible energy storage molecule. It can be made by dissociating some

molecules. How much heat is needed to make $1$ kg of H$2$ from water molecules or from

methane? In the latter, you can assume that the C will form graphite. Last, if methane reacts

with O$2$ and produces H$2$ and CO$2.$ Explain in detail what you compute. $($Extra: if electricity

costs $0\mathrm{.}1$ eur$/$kWh$,$ what is the minimum cost of $1$ kg of H$2$ in the two first cases? This ignores

the other production costs. You get $1$ extra point of this.