What is the mass percent of hydrogen in butane?

The molar mass of butane (C4H10) is 58.12 g/mol. The molar mass of hydrogen in butane is 10.81 g/mol. To calculate the mass percent of hydrogen in butane, you would divide the molar mass of hydrogen by the molar mass of butane and multiply by 100. This gives you a mass percent of approximately 18.6%.