The number of moles is given by: n= Given mass (m)/Molar Mass (M) M of C = 12 g/mol M of H = 1 g/mol Thus, the number of moles of carbon = 81.70g / 12gmol= 6.83moles and, the number of moles of hydrogen = 18.29/1g/mol = 18.29 moles The ration of C moles with hydrogen : H:C = 18.29moles/6.83moles= 2.67 ≈3