Question

Which has more atoms, 50 g of aluminium or 50 g of iron ? Illustrate your answer with the help of calculations.

(Atomic masses : Al = 27 u ; Fe = 25 u)

Answer 1

Mass of aluminium = 50g

We know that 27g of aluminium contain 6.022 × 10²³ aluminium atoms

Number of aluminium atoms in 27g  aluminium = 6.022 × 10²³

Number of aluminium atoms in 50g aluminium = 50 × 6.022 × 10²³/ 27

Hence, 50g aluminium has11.15 × 10²³ atoms.

Mass of iron = 50g

We know that 56g  iron contain 6.022 × 10²³ atoms

Number of atoms in 56g iron = 6.022 × 10²³

Number of atoms in 50g  iron = 50 × 6.022 × 10²³ / 56

Hence, 50g iron comprises 5.376 × 10²³ atoms.

It is clear that more number of atoms is present in 50g  aluminium than 50g  iron.