Calculate the relative molecular weights of the following C3H8 compounds.

To determine the relative molecular mass of a substance Mr, it is necessary to add the relative atomic masses of the elements that make up the compound, multiplying by the indices at the elements. The dimension of the relative molecular weight is a. e. m. (atomic mass unit). The dimension of the molar mass is g / mol!

Knowing the relative atomic masses of carbon and hydrogen, we calculate the relative molecular weight of propane (C3H8).

Ar (C) = 12 amu. eat.

Ar (H) = 1 amu. eat.

Mr (C3H8) = 3 * Ar (C) + 8 * Ar (H) = 3 * 12 + 8 * 1 = 36 + 8 = 44 amu. eat.