How many atoms are in 22.5g of pentane

mass of pentane = 22.5g

molar mass of pentane (C5H12) = 5 x 12.01 + 12 x 1.008

= 60.05 + 12.096

= 72.146g/mol

= 72.15g/mol

22.5g pentane x 1 mol pentane x 6.022 x 10^23 molecules ofpentane

72.15g pentane 1 mol pentane

= 22.5 x 6.022 x 10^23

72.15

= 1.88 x 10^23 pentane molecules

1 pentane molecule has 5 C + 12 H atoms = 5+12 = 17 atoms

Hence;

1.88 x 10^23 pentane molecules x 17 atoms

1 pentane molecule

= 31.925 x 10^23 atoms

= 3.2 x 10^22 atoms are present in 22.5g of pentane.

3.2 x 10^22 atoms