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yossup
Sep16-08, 11:47 PM
1. The problem statement, all variables and given/known data

A 1.10 mol sample of an ideal diatomic gas at a pressure of 1.20 atm and temperature of 420K undergoes a process in which its pressure increases linearly with temperature. The final temperature and pressure are 720K and 1.83atm.

Determine the work done by the gas.

Determine the heat added to the gas.

2. Relevant equations

E= 5/2 nRT

3. The attempt at a solution

So the change in internal energy I calculated to be 6860J.

So W + Q = 6860.

I can't figure out how to calculate W or Q because I don't know what kind of process this is (adiabatic, isobaric, isochoric, etc.) It just says pressure increases linearly with temperature. :(

Ygggdrasil
Sep16-08, 11:58 PM
Think of the ideal gas equation. If pressure increases linearly with temperature, what does that tell you about the process.

yossup
Sep17-08, 12:05 AM
isochoric! :D

Ygggdrasil
Sep17-08, 12:12 AM
Exactly. That make's the subsequent calculations really easy :)

yossup
Sep17-08, 11:40 AM
if it's isochoric, the work done by the gas should be zero but it says i'm wrong so it isn't isochoric?

Ygggdrasil
Sep17-08, 05:00 PM
Something's wrong with the problem. It says P increases linearly with T, but P_1/T_1 is not equal to P_2/T_2.

yossup
Sep18-08, 02:59 AM
isn't that because it's not at constant volume?

P1/T1 = P2/T2 only at constant volume... :(

Ygggdrasil
Sep19-08, 08:14 PM
But if P increases linearly with T then P = c T, where c is a constant, so P/T = c implying that P_1/T_1 = P_2/T_2