For the hydrocarbon toluene for which the grams of carbon per gram of hydrocarbon is 0.9125 calculate the mass of H that combines with 1 g. of carbon.

0.09589 g

Explanation:

The question tells us that tolouene is a hydrocarbon. Which means it made up of hydrogen and carbon only. So per gram of hydrocarbon, 0.9125 of it is carbon and the rest is hydrogen.

mass of carbon in 1g of tolouene = 1 g * 0.9125 = 0.9125 g

mass of hydrogen in 1 g of tolouene = 1 g - 0.9125 g = 0.0875 g

Then use their mass ratio to obtain the calculate the mass of hydrogen in a different sample of tolouene.

mass (hydrogen) : Mass (carbon)

0.0875 g : 0.9125 g

x g : 1 g

and if you cross multiply:

0.9125x = 0.0875

x = 0.09589 g