# Question #f79bb

##### 1 Answer

In order to calculate the mass of 2.1 moles of acetylene, you must first determine the mass of one mole, which is its molar mass. The mass of one mole of a substance is its atomic weight in grams/mole (g/mol). Then multiply the molar mass times the number of moles given in the question.

To determine the molar mass of

**Molar mass of #"C"_2"H"_2#.**

C: 12.011g/mol x 2 = 24.022g/mol

H: 1.008g/mol x 2 = 2.016g/mol

Total: 26.038g/mol

Molar mass of

**Calculate the mass of 2.1 mol #"C"_2"H"_2#.**

The mass of 2.1 moles