How many moles of hydrogen were in the original sample that underwent combustion ?

Question

A certain compound was found to have a molar mass of 72.106 g. A 3.192 g sample of this compound was burned in pure oxygen gas. The measured amount of CO2 produced was 7.793 g, while that of H2O was 3.190 g. No other products were produced in the reaction.

Answer 1

3.19/18 moles of H2, so double that for moles of H atoms.