Question

Complete the following calculations.

Calculate the mass of calcium that will contain the same number of atoms as are present in $3.2$ gm of sulphur.
[Atomic masses: $S=32,Ca=40$ g/mol]

Answer 1

$32$ g of sulphur $=1$ mole

$\therefore$ $3.2$ g of sulphur $=0.1$ mole.

0.1 mole of sulphur contains $0.1N_A$ atoms of sulphur.

No. of atoms of $Ca=$ No. of atoms of $S=0.1N_A$

No. of moles of $Ca=0.1$ mole

mass of 0.1 mole of Ca $=40\times 0.1$ gm

$=4$ g

Ans: $4$