10 minutes maximum! Can you do it in 5?

Q1-3. These questions are about the pressure of air inside a bike tyre:

1. Which of these sentences best explains the change in pressure if the tyre is heated?

• A. The pressure increases because there are more particles of air inside the tyre.
• B. The pressure increases because the particles hit the sides harder and more often.
• C. The pressure decreases because there are more spaces between the particles of a hot gas.
• D. The pressure decreases because the particles move faster so do not hit the sides so frequently.

2. Which of these rows describes the change in pressure and particle speed if the temperature is kept constant, but more air is pumped into the tyre?

 Pressure Particle Speed A increases stays the same B increases increases C stays the same stays the same D stays the same increases

3. When a cyclist sits on the bike, the tyre is compressed. Assuming the temperature remains constant, how does this compression change the volume of the tyre and the pressure in the tyre?

 Volume Pressure A increases stays the same B increases increases C decreases stays the same D decreases increases

4. As any gas is cooled, the particles slow down. At what temperature do the particles have the least kinetic energy?

• A. 0 °C
• B. -100 °C
• C. -273 °C
• D. -373 °C
5+6. These questions are about the kelvin scale of temperature.

5. What is -173 °C in kelvin?

• A. 100 K
• B. 73 K
• C. -173 K
• D. -346 K

6. What is 400 K in °C?

• A. 673 °C
• B. 173 °C
• C. 127 °C
• D. -127 °C
7+8. A sealed gas syringe contains a volume of 30 cm3 of gas at a pressure of 100 kPa.

7. The syringe is pulled out slowly, increasing the volume to 75 cm3 whilst the temperature remains constant.

What is the new pressure in the gas?

• A. 250 kPa
• B. 150 kPa
• C. 66 kPa
• D. 40 kPa

8. At what volume would the pressure be 125 kPa?

• A. 18 cm3
• B. 24 cm3
• C. 38 cm3
• D. 50 cm3
An empty metal drinks bottle contains air at 300 K and at a pressure of 1 x 105 Pa. (the volume remains constant).

9. What is the pressure in pascals when the bottle is left in strong sunlight and the temperature reaches 350 K?

• A. 1.2 x 105
• B. 8.6 x 105
• C. 8.6 x 104
• D. 3.5 x 105

10. At what temperature will the pressure be 9 x104 Pa?

• A. 270 °C
• B. 60 °C
• C. 24 °C
• D. -3 °C