Question

What is the empirical formula of a compound that is 85.6% carbon and 14.4% hydrogen by weight?

Answer 1

1) since we have percentages, we can assume we have 100 grams of the compound.

85.6% Carbon---> 85.6 grams of C
14.4% Hydrogen--> 14.4 grams of H

2) we need to convert the grams to moles for each one using their molar masses.

molar mass of C= 12.0 g/mol
molar mass of H= 1.01 g/mol


`85.6 g C ( (1 mol C)/(12.0 grams) )= 7.13 mol C`


`14.4 g H ( (1 nol H)/(1.01 grams) )= 14.3 mol H`

3) divide each mole by the smallest value(7.13) to find the ratios

Carbon--->
`(7.13)/(7.13) = 1.0`
Hydrogen--->
`(14.3)/(7.13)= 2.0`

4) use these ratios to write the empirical formula.

CH₂