DP Physics (last assessment 2024)

Question 18M.3.SL.TZ2.7c

Date	May 2018	Marks available	[Maximum mark: 3]	Reference code	18M.3.SL.TZ2.7c
Level	SL	Paper	3	Time zone	TZ2
Command term	Determine	Question number	c	Adapted from	N/A

[Maximum mark: 3]

18M.3.SL.TZ2.7c

A cylinder is fitted with a piston. A fixed mass of an ideal gas fills the space above the piston.

M18/4/PHYSI/SP3/ENG/TZ2/07._01

The gas expands isobarically. The following data are available.

$\begin{array}{*{20}{l}} {{\text{Amount of gas}}}&{ = 243{\text{ mol}}} \\ {{\text{Initial volume of gas}}}&{ = 47.1{\text{ }}{{\text{m}}^3}} \\ {{\text{Initial temperature of gas}}}&{ = -12.0{\text{ °C}}} \\ {{\text{Final temperature of gas}}}&{ = + 19.0{\text{ °C}}} \\ {{\text{Initial pressure of gas}}}&{ = 11.2{\text{ kPa}}} \end{array}$

(c)

Determine the thermal energy which enters the gas during this expansion.

[3]

Markscheme

ΔU «= $\frac{3}{2}$ nRΔT» = 1.5 × 243 × 8.31 × (19 – (–12)) = 9.39 × 10⁴

Q «= ΔU + W» = 9.39 × 10⁴ + 6.27 × 10⁴

Q = 1.57 × 10⁵ «J»

Accept 1.60 × 10⁵ if 66.1 × 10³ J used

Accept 1.55 × 10⁵ if 61.6 × 10³ J used

[3 marks]

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Option B: Engineering physics

Option B: Engineering physics » Option B: Engineering physics (Core topics) » B.2 – Thermodynamics

Option B: Engineering physics » Option B: Engineering physics (Core topics)

Question 18M.3.SL.TZ2.7c

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