The molar mass of carbon dioxide, CO2, is

Explanation

Adding one carbon at 12 and two oxygens at 16 each gives 12 + 32, that is 44 g per mole. The value 28 belongs to carbon monoxide and 32 to oxygen gas, both of which appear here because they are the neighbouring molecules students confuse it with. Molar mass in grams per mole is numerically equal to relative molecular mass.