The molar mass of a compound is the mass in grams of 1 mole of that substance, a property expressed in units of grams per mole (g/mol) Because the definitions of both the mole and the formula mass are based on the same reference substance, 12 C, the molar mass of any compound is numerically equivalent to its formula weight in amu.
Molar volume at STP can be used to convert from moles to gas volume and from gas volume to moles. The equality of \(1 \: \text{mol} = 22.4 \: \text{L}\) is the basis for the conversion factor. Example \(\PageIndex{1}\): Converting Gas Volume to Moles The formula mass of a covalent compound is also called the molecular mass. A convenient amount unit for expressing very large numbers of atoms or molecules is the mole. Experimental measurements have determined the number of entities composing 1 mole of substance to be 6.022 × 1023, a quantity called Avogadro’s number. Molecular weight and molar mass are not exactly the same, but they are closely related terms. Molecular weight refers to the average mass of the molecule. On other hand, the molar mass is the mass of one mole of a substance. The mass of one mole of a substance is equal to that substance’s molecular weight. For example, the mean molecular weight of water is 18.015 atomic mass units (amu), so one mole of water weight 18.015 grams. Key Terms. mole: The amount of substance of a system that contains as many elementary entities as there are atoms in 12 g of carbon-12.The meaning: Molecular mass is the mass of a single molecule. This means that molecular mass is the mass of one atom or one molecule. Molar mass is the mass of a molecule as a whole. The molecular mass is the sum of the masses of all the atoms in a molecule. Units: Molecular mass is measured in grams (g).
Thus, 98 g of H 2 SO 4 = 1 mole of H 2 SO 4. 392 g of H 2 SO 4 = 4 moles of H 2 SO 4. 2) 1 mole of CO 2 = 22.4 litres at STP. i.e. 22.4 litres of CO 2 at STP = 1 mole. 44.8 litres of CO 2 at STP = 2 moles CO 2. 3) 1 mole of O 2 molecules = 6.022 x 10 23 molecules. 6.022 x 10 23 molecules = 1 mole of oxygen molecules. NAjCPv.