Experimental Gas Laws

Question 1

What is Boyle’s Law?

Answer 1

For a fixed mass of gas at constant temperature pV = constant.

Question 2

What is Charle’s Law?

Answer 2

For a fixed mass of gas at constant pressure V/T = constant.

Question 3

What is the Pressure Law?

Answer 3

For a fixed mass of gas at constant volume p/T = constant.

Question 4

Define a isothermal process.

Answer 4

An isothermal process is a change of a system, in which the temperature remains constant.

Question 5

Define an isobaric process.

Answer 5

A process in which the pressure stays constant.

Question 6

Explain the Boyle’s Law experiment.

Answer 6

• The length of the air represents the volume as the tube has a constant cross-sectional area.
• Initial reading taken of pressure using pressure gauge and volume V represented by length L.
• Pressure changed (probably using a footpump).
• Readings again taken of p and L (representing volume).
• Repeated for at least seven different pressures.
• Results could be plotted of p against 1/V and the graph will be a straight line passing through the origin

Question 7

What happens when work is done to change the volume of a gas?

Answer 7

Energy must be transferred by heating to keep pressure constant, and work done by a gas on a piston can be given by pΔV.

Question 8

Explain Charle’s Law Experiment.

Answer 8

• A volume of air is trapped below the concentrated sulphuric acid.
• The length of the air represents the volume as the capillary tube has a constant cross-sectional area.
• Initial reading taken of temperature T and length L at room temperature.
• Bunsen burner used to increase temperature by approximately 10 °C.
• Bunsen removed and water stirred to obtain even temperature.
• Readings taken of T and L.
• Bunsen replaced under beaker.
• Repeated for at least seven further higher temperatures.

Question 9

Explain the Pressure Law Experiment

Answer 9

• Initial reading taken of pressure on pressure gauge and temperature T using thermometer.
• Heater used to increase temperature.
• Water stirred to ensure even temperature before taking readings.
• Readings again taken of p and T.
• Repeated for at least seven different temperatures.