A scientist cooled the air inside a container: The temperature of the air changed from 20 °C to 0 °C - AQA - GCSE Physics Combined Science - Question 2 - 2019 - Paper 1

To find the mass of ice produced, we use the formula for latent heat:

$m = \frac{Q}{L}$

where:

• $Q$ is the change in internal energy (0.70 kJ = 700 J)
• $L$ is the specific latent heat of fusion (330 kJ/kg = 330,000 J/kg)

Substituting these values:

$m = \frac{700}{330000} \approx 0.00212 \text{ kg}$

Thus, the mass of ice produced is approximately 0.0021 kg.

As the temperature decreases from 20 °C to -190 °C, the argon gas particles lose energy and move closer together. Initially, in the gaseous state, the particles are far apart and move freely in random directions. As cooling continues, they start to slow down, transitioning to the liquid state where they are closer together but still able to slide past one another.

Finally, at -190 °C, the argon particles arrange themselves in a fixed position, forming a solid. This is characterized by a regular arrangement, where the particles vibrate in place rather than move freely.