What amount of aluminum is contained in a 10.8 g sample of this metal?

In order to find the amount of a substance, it is necessary to divide its mass by its molar mass.

The molar mass of aluminum is:

M Al = 27 grams / mol;

This shows that one mole of metal weighs 27 grams.

The amount of the substance will be equal to the ratio of the mass of the metal to its molar mass:

N Al = 10.8 / 27 = 0.400 mol;