Empirical formula

[Clari]

A gas X has a density of 1.187gdm^-3 at 1.01 atm. & 35^oC. Gas X contains 79.8% by mass of C & 20.2% by mass of H. Find the empirical formula of X.

Here are my steps:

mole ratio of C to H = 79.8/12.01 : 20.2/1.008
= 7: 20
In that case, its empirical formula is C_{7}H_{20} while I don't think there is a gas with this formula, the closest one is C_{7}H_{16}. Can anyone help me with it?

I know what's wrong now....I have mistaken it as the molecular formula...hheee...being silly...so the answer should be CH_{3}.

[Sirus]

Ok.

Note: to make your Latex fit into the text, use "itex" and "/itex" in the brackets instead of "tex" and "/tex".

[chem_tr]

It is very simple; just simplify the ratio, \frac {7}{20} to obtain \frac {1}{0,35}. As you know that a carbon-containing gas must contain up to five carbon atoms, a gas with seven carbons would not be logical. So just simplify the ratio for your needs.