PhysicsLAB Practice Problems
Heat Cycle

Directions: On this worksheet all questions are based on this PV diagram. The y-axis represents pressure measured in kPa while the x-axis represents volume measured in cubic meters. The enclosed gas used throughout this problem is Helium, a monatomic gas which has a specific heat for constant volume of CV = 3/2R; and a specific heat for constant pressure of CP = 5/2R.
PV diagram

Question 1  40 grams of gas follow the process AB, BC, CD, and DA as shown above. You are given that the temperature at position A is T1 = 31ºC and the temperature at position B is T2 = 658ºC.

How many moles of helium are present in the container?
Question 2  In which processes was heat removed from the gas?
Question 3  If P1 equals 120 kPa, then what is the value of P2?
Question 4  What is the value of V1, the original volume of the container?
Question 5  If during this heat cycle the volume of the gas expands to a maximum value of V2 = 4V1, what is the temperature at position D?
Question 6  What is the average translational kinetic energy of a gas molecule at poisiton D?
Question 7  In which processes was no work done on or by the gas?
Question 8  By how much does the internal energy of the gas increase during process BC?
Question 9  What is the net work done by the gas during this heat cycle?
Question 10  How much heat is added during one complete cycle?
Question 11  What is the ideal Carnot efficiency for this heat cycle?
Question 12  What is the actual efficient of this heat cycle?

Copyright © 1997-2017
Catharine H. Colwell
All rights reserved.
Application Programmer
Mark Acton