Isothermal Compression and Entropy Change

  • #1

Homework Statement



A 740g quantity of an ideal gas undergoes a reversible isothermal compression at a temperature of 330 K. The compression reduces the volume of the gas from 0.40 m3 initially, to 0.32 m3 finally. The entropy change of the gas is equal to:

A) -43 J/K B) -150 J/K C) 43 J/K D) 150 J/K E) 0 J/K


Homework Equations



ΔS = nR*ln(Vf/Vi)

The Attempt at a Solution



I actually know exactly how to solve this problem. The only thing is, I haven't been able to determine n, the number of moles, without being given the molar mass.
Is there some method to determine n that I'm missing, or has my prof omitted a vital piece of information (the molar mass)?
 

Answers and Replies

  • #2
Andrew Mason
Science Advisor
Homework Helper
7,610
356

Homework Statement



A 740g quantity of an ideal gas undergoes a reversible isothermal compression at a temperature of 330 K. The compression reduces the volume of the gas from 0.40 m3 initially, to 0.32 m3 finally. The entropy change of the gas is equal to:

A) -43 J/K B) -150 J/K C) 43 J/K D) 150 J/K E) 0 J/K


Homework Equations



ΔS = nR*ln(Vf/Vi)

The Attempt at a Solution



I actually know exactly how to solve this problem. The only thing is, I haven't been able to determine n, the number of moles, without being given the molar mass.
Is there some method to determine n that I'm missing, or has my prof omitted a vital piece of information (the molar mass)?
You need the molar mass.

AM
 

Related Threads on Isothermal Compression and Entropy Change

Replies
5
Views
2K
  • Last Post
Replies
2
Views
846
Replies
1
Views
3K
  • Last Post
Replies
17
Views
531
Replies
1
Views
679
Replies
8
Views
3K
Replies
5
Views
4K
Replies
5
Views
3K
Replies
2
Views
8K
  • Last Post
2
Replies
49
Views
2K
Top