Pressure/Introductory Thermodynamics

  • Thread starter JamesL
  • Start date
  • #1
33
0
Not sure what I am doing wrong...

Homework Statement


A chemical reaction takes place in a container
of cross-sectional area 100 cm2. As a result of
the reaction, a piston is pushed out through 20
cm against an external pressure of 567 torr.
What is the value for w for this reaction?
(Sign does matter.) Answer in units of J.

Homework Equations



w = - (Pressure)(Change in Volume)


The Attempt at a Solution



Cross sectional area = 100 cm^2 = .01 m^2
Change is piston distance = 20cm = .2 m

Pressure = 567 torr x 133.322 = 75593.574 Pa


Solution disregarding sign = [75593.574 kg/(m*s^2)][.01 m^2][.2 m]

---> 151.188 J

However this is coming up as incorrect.
 

Answers and Replies

  • #2
Doc Al
Mentor
45,247
1,594
Looks OK to me. Why are you ignoring the sign when it says "sign does matter"?
 
  • #3
33
0
Looks OK to me. Why are you ignoring the sign when it says "sign does matter"?

This is why a separate set of eyes is always helpful!
 

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