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A scientist cooled the air inside a container: 1 - AQA - GCSE Physics Combined Science - Question 2 - 2019 - Paper 1
Question 2
A scientist cooled the air inside a container: 1. The temperature of the air changed from 20 °C to 0 °C. Explain how the motion of the air molecules caused the pre... show full transcript
Worked Solution & Example Answer:A scientist cooled the air inside a container: 1 - AQA - GCSE Physics Combined Science - Question 2 - 2019 - Paper 1
Step 1
Explain how the motion of the air molecules caused the pressure in the container to change as the temperature decreased.
Answer
As the scientist cooled the air, the temperature decrease led to a reduction in the kinetic energy of the air molecules. As their kinetic energy lessened, the molecules moved slower and collided with the walls of the container less frequently and with less force. This resulted in a decrease in pressure within the container.
Step 2
Calculate the mass of ice produced.
Answer
To find the mass of ice produced, we can use the relationship between internal energy and latent heat:
Given:
- Change in internal energy, (0.70, \text{kJ} = 700, \text{J})
- Latent heat of fusion of water, (L = 330, \text{kJ/kg} = 330000, \text{J/kg})
Using the formula:
Solving for mass (m):
Therefore, the mass of ice produced is approximately (0.0021, \text{kg} ).
Step 3
Step 4
Explain the changes in the arrangement and movement of the particles of the argon as the temperature of the air decreased.
Answer
As the temperature decreases from 20 °C to -190 °C, the arrangement and movement of argon particles undergoes significant changes:
- Cooling: As the argon cools, the particles lose kinetic energy. Consequently, they move slower.
- Transition to Liquid: When the temperature falls to around the boiling point, the argon transitions from a gas to a liquid. The particles move closer together but maintain some random motion.
- Transition to Solid: Continuing to cool to -190 °C, the argon freezes into a solid. The particles are closely packed in a regular arrangement, minimizing their movement, and vibrate around fixed positions.
These changes illustrate how thermal energy affects particle states and arrangements.