(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

Starting with 2.50 mol of N2 gas (assumed to be ideal) in a cylinder at 1.00 atm and 20C, a chemist first heats the gas at constant volume, adding 1.52x10^4J of heat, then continues heating and allows the gas to expand at constant pressure to twice its original volume. Calculate the final temperature of the gas.

2. Relevant equations

PV=nRT

ΔU=Q-W

ΔU=nCvΔT

3. The attempt at a solution

The first part suggests that the system is in a constant volume. Thus:

ΔU=Q

nCvΔT=Q

(2.5mol)(5/2)(R)(Tf-20)=1.52x10^4

I solve for Tf and I get 312.5C.

Now the next part suggests the system is at a constant pressure and the volume doubles.

So I use PV=nRT where n, R and P are constant.

V/T=V/T

1/312.5C=2/T

I solve for and I get 625C. However the answer in the back is 899C. What am I doing wrong?

Thanks!

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# Homework Help: The final temperature of a gas?

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