Question #39025

1 Answer
Aug 19, 2017

CH_4CH4

Explanation:

As always, it is useful to assume 100*g100g of unknown compound, and then we interrogate its atomic composition:

"Moles of C"Moles of C == (75*g)/(12.011*g*mol^-1)=6.24*mol*C75g12.011gmol1=6.24molC

"Moles of H"Moles of H == (25*g)/(100794*g*mol^-1)=24.8*mol*H25g100794gmol1=24.8molH

And we divide thru by the SMALLEST molar quantity to get......

C_((6.24*mol)/(6.24*mol))H_((24.8*mol)/(6.24*mol))=CH_4C6.24mol6.24molH24.8mol6.24mol=CH4.

Clearly, the question was devised purely for pedagogy, as the unknown compound is methane on the basis of these data - it would be hard to collect combustion data on a gas.