Question

An insulated rigid tank contains 1.5 kg of helium at 30∘C and 500 kPa. A paddle wheel with a power rating of 0.1 kW is operated within the tank for 30 minutes. Cvof helium = 3.12 KJ/Kg.K

Problem 7A. Calculate the net work done by helium, in kJ. Enter the number with appropriate sign.

Problem 7B. What is the final temperature of helium, in ∘C ?

Problem 7C. What is the final pressure of helium, in kPa?

Problem 7D. What is the change in entropy of helium, in J/K?

Problem 7E. How much entropy is produced during the process, in J/K?

Problem 7F. What are the causes of the entropy production?

a)Violation of the second law
b)An adiabatic process
c)The stirrer work
d)The increase in temperature

Answer 1

210
70
12
1000
800
the increase in temperature

Answer 2

all wrong

Answer 3

-180
69 C
563.5
550
550
b)

Answer 4

all correct except last one. option is wrong/more than one option should be included.