Paper 3: Required practical 8 - Boyle's and Charles' law

Question 1

How can you measure the cross-sectional are of the inside of a syringe?

Answer 1

Remove the plunger and then, using a micrometer, measure the diameter of the seal

Question 2

Why should the clip used to seal the tubing be as close as possible to the syringe tip?

Answer 2

The volume of air trapped in the tubing should be as small as possible so that it is negligible in comparison to the volume in the syringe

Question 3

How can the mass hanger be attached to the plunger of the syringe?

Answer 3

• Small piece of string can be tied to the plunger to form a loop
• The hanger can then hook onto this loop

Question 4

Why should the syringe be clamped above the region of the plunger’s motion?

Answer 4

• Clamping the syringe can distort the barrel and hinder the motion of the plunger
• By clampingabove the region in which the plunger moves, this problem is avoided
• Ensures that the scale on the syringe isn’t covered by the clamp

Question 5

Why should the syringe be clamped at a relatively high position?

Answer 5

So the plunger has space to move down as masses are added

Question 6

What is the relationship that can be formed when a graph of 1/V against P is plotted?

Answer 6

Straight line through the origin

Question 7

Why might a straightline not be produced when plotting a graph of 1/V agaisnt P?

Answer 7

• Plunger may have experienced some resistance to its motion as masses were added
• Sticking of the plunger, would create error that may result in an inaccurate mesured change in volume

Question 8

What safety precautions should be taken when using concentrated sulfuric acid?

Answer 8

Safety goggles and gloves

Question 9

What safety precautions should be taken when working with a hot beaker of water?

Answer 9

• Avoid touching the hot beaker with bare hands
• Ensure it’s handled with care to avoid spillages
• Heatproof mat should be used to protect the bench

Question 10

What should you do before recording each measurement of water temperature?

Answer 10

Stir the water so the water is an appropriate and accurate reflection of the average temperature of the water in the beaker

Question 11

How can an estimate of absolute zero be obtained from a graph of length of air sample against temperature?

Answer 11

Graph will be: L=mθ + c
Sub in values to find c and then rearrange for θ when L=0 to obtain absolute zero