What is the mass of:
(a) 1 mole of nitrogen atoms
(b) 4 moles of aluminium atoms?
(c) 10 moles of sodium sulphite (Na2S03)?
(Atomic masses: N = 14 u, AI= 27 u, Na = 23 u, S = 32 u and 0 = 16 u)
(a) Mass of 1 mole of nitrogen atoms = Atomic mass of nitrogen atom
Atomic mass of nitrogen atom = 14u
Therefore, Mass of 1 mole of nitrogen atoms = 14 g
(b) Mass of 1 mole of Aluminium atoms = Atomic mass of Aluminium
Atomic mass of Aluminium = 27 u
Mass of 1 mole of aluminium atom = 27 g
Therefore, mass of 4 moles of aluminium atoms = 4 X 27 = 108 g
(c) Mass of 1 mole of sodium sulphite = Molecular mass of sodium sulphite (Na2SO3) in grams
Molecular mass of Na2SO3 in grams = Mass of 2Na + Mass of S +Mass of 3 '0'
= 2 X 23 + 32 + 3 X 16
= 46 + 32 + 48
= 126 g
Therefore, Mass of 10 moles of Na2SO3 = 126 x 10 g = 1260 g