Two bottles, I and II, have the same volume and are at the same temperature - VCE - SSCE Chemistry - Question 17 - 2007 - Paper 1

To determine the number of atoms in each bottle, we can use the molar mass of the gases.

• The molar mass of argon (Ar) is approximately 40 g/mol.
• The molar mass of neon (Ne) is approximately 20 g/mol.

Calculating the number of moles for each:

For argon: $n_{Ar} = \frac{10\text{ g}}{40\text{ g/mol}} = 0.25 \text{ mol}$

For neon: $n_{Ne} = \frac{10\text{ g}}{20\text{ g/mol}} = 0.5 \text{ mol}$

Now, we convert moles to atoms using Avogadro's number, approximately $6.02 \times 10^{23}$ atoms/mol:

For argon: $N_{Ar} = 0.25 \text{ mol} \times 6.02 \times 10^{23} \text{ atoms/mol} \approx 1.51 \times 10^{23} \text{ atoms}$

For neon: $N_{Ne} = 0.5 \text{ mol} \times 6.02 \times 10^{23} \text{ atoms/mol} \approx 3.01 \times 10^{23} \text{ atoms}$

Thus, the number of atoms in bottle II is approximately double that in bottle I.