Question

If 1 gram of Carbon contains x atoms, what will be the number of atoms in 1 gram of Magnesium ?

Answer 1

Carbon (C)

1. 1 mole of C = 12 g (since mole of C = gram molecular mass of C).
2. 1g C= $\frac{1}{12}$mole and 1g of C contains $\mathrm{x}$ atoms. Therefore $\frac{1}{12}$mole of C has $\mathrm{x}$ atoms.
3. Equal number of moles of all the elements contain equal atoms, so $\frac{1}{12}$mole of Mg also contains $\mathrm{x}$ atoms.

Magnesium (Mg)

• 1 mole of Mg = 24g, therefore, 1 g Mg = $\frac{1}{24}$mole.
• $\frac{1}{12}$ mole of Mg = x atoms.
• $\frac{1}{24}$ mole of Mg = $x\times \frac{12}{24}$= $\frac{x}{2}$ atoms.
• Hence 1g of Mg has $\frac{x}{2}$ atoms.