## Problem 8.31

$\Delta U=q+w$

hannah_flagg_3F
Posts: 10
Joined: Wed Sep 21, 2016 2:57 pm

### Problem 8.31

The problem asks you to calculate the heat released by 5.025 g of Kr(g) at 0.400 atm as it cools from 97.6 C to 25 C at (a) a constant pressure and (b) a constant volume.

Now, I know you use the formula Cp=5/2R to solve for the heat capacity for constant pressure and Cp=3/2R to solve for the heat capacity for constant volume, and you use the R value, 8.314 J/K*mol. In the solution manual, it solves the problem by leaving the temperature change in degrees celsius, but the gas constant you use has the temperature in Kelvin. So why the discrepency?

mikezargari
Posts: 20
Joined: Wed Sep 21, 2016 2:56 pm
Been upvoted: 1 time

### Re: Problem 8.31

The units for delta T are arbitrary because the difference between your final T and initial T are going to be the same whether you are calculating it in celsius or kelvin.