A gas is found to be 85.7 carbon and 14.3 hydrogen by mass. its molecular mass was found to be 98.1 g/mol using the method of this experiment. What is the molecular formula of this gas?

Question

anonymous · Answer

Let there is 100 g of this gas.
Mass of C: 85.7 g          Mass of H: 14.3 g
No. of mole of C: 85.7/12=7.14
No. of mole of H: 14.3/1=14.3
Mole ratio between C and H= 1:2
therefore, the empirical formula of this gas: CH2
molecular mass:
98.1=(12+1+1)xN
N=7
So the molecular formula of this gas is C7H14.