Apparatus:
Boyle's law apparatus with hand pump, thermometer.
Diagram:
Procedure:
1. Note the temperature of the laboratory.
2. Open the pressure valve so that the oil and trapped air are at atmospheric pressure (about 100kPa).
3. Note the initial pressure
(about 100kPa) and volume
of the trapped air.
4. Attach the hand pump to the apparatus.
Note it actually is a foot pump but please operate it only by hand.
5. Pressurise the oil and trapped air to between 200 and 300kPa. You will need to close the valve quickly to maintain this pressure.
6. Note the maximum pressure,and corresponding minimum volumereached.
7. Take about 6 further pressure,and volumereadings by slowly releasing the pressure of the oil down to atmospheric pressure again. You should be prepared to estimate both pressures and volumes on both scales.
8. Tabulate your readings and also for each set of readings calculate; (
) and (
).
9. Retake the laboratory temperature.
10. Plot a graph ofagainst
11. Measure the gradient,
of your graph.
12. Comment on how well the trapped air has obeyed Boyle's law.
You should make reference to your graph.
13. What is the gradient,equal to?