Question

One mole of an unknown sample contains 120 g of carbon and 30.3 g of

hydrogen. What is the empirical formula of the compound? Show your work.

Answer 1

atomic mass of carbon is C = 12 g/mol

atomic mass of hydrogen is H = 1 g/mol

now number of carbon atoms

`N_c = (120)/(12) = 10`

Similarly the number of hydrogen atoms are

`N_H = (30.3)/(1) = 30`

so Carbon atom and hydrogen atom must be in ratio of 10:30

so the ratio is 1:3

now the empirical formula is always in simplest form

`CH_3`