A sample of ideal monatomic gas undergoes a slow

PHYSICS · Multi-part · A Level · Physics · Further mechanics and thermal physics · Further mechanics and thermal physics

Problem

0.45\,\text{mol}

sample of ideal monatomic gas undergoes a slow, isobaric expansion at

95\,\text{kPa}

from an initial volume of

0.60\,\text{m}^3

to a final volume of

0.85\,\text{m}^3

. During the expansion the surroundings supply

58\,\text{kJ}

of energy by heating. (1) Calculate the work done on the gas during the expansion. State both the magnitude and sign, and explain how the sign follows from the definition of work in thermodynamics. (2) Determine the change in internal energy

\Delta U

of the gas, including the correct sign. Show all steps in your reasoning. (3) Describe, in words, the overall direction of energy flow between the system and surroundings for this process, citing the numerical results you obtained.

Related theory

Internal Energy
First Law of Thermodynamics
Laws of Thermodynamics
The first law of thermodynamics
Thermodynamics

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