1) N(H) = 3.28·10²⁴; number of hydrogen atoms.
n(H) = N(H) ÷ Na(Avogadro constant).
n(H) = 3.28·10²⁴ ÷ 6.022·10²³ 1/mol.
n(H) = 5.44 mol.
According to molecular formula of butane: n(H) : n(C) = 8 : 3.
n(C) = (5.44 mol · 3) ÷ 8.
n(C) = 2.04 mol; amount of substance.
N(C) = 2.04 mol · 6.022·10²² 1/mol.
N(C) = 1.23·10²⁴, number of carbon atoms.
2) n(C₃H₈) : n(C) = 1 : 3.
n(C₃H₈) = 2.04 mol ÷ 3.
n(C₃H₈) = 0,68 mol.
m(C₃H₈) = n(C₃H₈) · M(C₃H₈).
m(C₃H₈) = 0.68 mol · 44.1 g/mol.
m(C₃H₈) =29.99 g; mass of the sample.