What amount of the substance is contained in a) in a 168 g sample of iron; b) in a 160 g portion of methane (CH4).

In order to find the amount of substances, it is necessary to divide the masses of these substances by their molar masses.

The amount of substance in the iron sample:

M Fe = 56 grams / mol;

N Fe = 168/56 = 3 mol;

The amount of substance in the sample of methane:

M CH4 = 12 + 4 = 16 grams / mol;

N CH4 = 160/16 = 10 mol;