Answers to AQA GCSE Doing work on gases

Practice Questions

1. What does the term, doing work mean?

Doing work means to transfer energy.

2. A bike tyre is inflated. During the inflation, the temperature of the tyre increases. Explain the increase in temperature.

During inflation of the tyre work is done on the gas, so energy is transferred to the gas. This means that the internal energy store of the gas particles increases.  

As the gas now has a higher internal energy, its temperature increases. 

3. A medical company invents a new freezing spray for warts. It uses compressed air which is sprayed onto the wart. As a result the wart is frozen and then falls off. Explain how this spray can freeze the wart. 

As the compressed air is sprayed onto the wart it  expands, it does work to transfer energy to the thermal energy store of the surroundings, so the temperature of the air and wart will decrease causing the wart to freeze.