Question

Explain molar mass.

Answer 1

• The mass of one mole of a substance (element/compound) in grams is called its molar mass.
• The molar mass of any element in grams is numerically equal to the atomic mass of that element in u.
  e.g.

Element	Atomic mass (u)	Molar mass (g mol−1)
H	1.0	1.0
C	12.0	12.0
O	16.0	16.0

• Similarly, the molar mass of a polyatomic molecule, in grams is numerically equal to its molecular mass or formula mass in u.
  e.g.

Polyatomic substance	Molecular/formula mass (u)	Molar mass (g mol−1)
O2	32.0	32.0
H2O	18.0	18.0
NaCl	58.5	58.5