3 (a) Carbon dioxide is one of the gases in the Earth's atmosphere - Edexcel - GCSE Chemistry Combined Science - Question 3 - 2019 - Paper 1

One factor is human activity, specifically the burning of fossil fuels which increases CO₂ levels in the atmosphere. Another factor is natural processes, such as photosynthesis in plants which decreases CO₂ levels.

Carbon dioxide has a low boiling point due to weak intermolecular forces (Van der Waals forces) between the molecules. These forces require less energy to overcome, allowing CO₂ to transition to gas at lower temperatures.

First, calculate the number of moles:

$ext{moles} = \frac{0.11 ext{ g}}{44 ext{ g/mol}} = 0.0025 ext{ mol}$

Next, use Avogadro's constant to find the number of molecules:

$ext{number of molecules} = 0.0025 ext{ mol} \times 6.02 \times 10^{23} \text{ molecules/mol} = 1.51 \times 10^{21}$

Thus, the answer is approximately $1.5 \times 10^{21}$ molecules.