The gas laws
4 marks · NormalA student investigates Boyle's law using a sealed syringe, as shown.
The initial pressure is kPa and the initial volume is cm. By pushing the plunger, the volume is changed to cm while temperature remains constant.
State Boyle's law.
Calculate the final pressure inside the syringe.
Work this out on paper, then compare with the answer and worked solution below. With a free account you can submit written answers for marking.
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(a) The pressure of a fixed mass of gas is inversely proportional to its volume at constant temperature (or, pV = constant).
(b) 149 kPa
Common mistakes: Arithmetic slip in rearrangement
Show mark scheme and worked solution
Marking points
B1 (a) · 1 mark · Correctly states Boyle's law (inverse relationship between pressure and volume at constant temperature).
M1 (b) · 1 mark · Uses and substitutes correct values.
M2 (b) · 1 mark · Correctly rearranges and calculates value. (follow-through)
A1 (b) · 1 mark · Final answer with correct unit. (follow-through)
Worked solution
a) Boyle’s law states that: The pressure of a fixed mass of gas is inversely proportional to its volume at constant temperature.
Therefore, final pressure is 149 kPa (to 3 s.f.).