Question

A compound composed of hydrogen and oxygen is found to contain 0.59 g of hydrogen and 9.40 g of oxygen. The molar mass of this compound is 34.0 g/mol. Find the empirical and molecular formulas.

Answer 1

number of moles = mass / Mr

no. of mol. of hydrogen = 0.59/1 =0.59

no. of mol. of oxygen = 9.40/16 = 0.5875

divide both by smallest value which is 0.5875 which gives you 1 mole of oxygen & 1 mole of hydrogen

OH is the empirical formula but because the Mr is 34, we must multiply H by 2 and O by 2 and that’ll be H2O2 which is hydrogen peroxide

Explanation: hope this helps :)