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

From Giancoli's UC Berkeley edition Physics for Engineers and Scientists:

A 2.00 mole sample of N2 (nitrogen) gas at 0 degrees C is heating to 150 degrees C at constant pressure (1.00 atm). Determine the heat added to it.

2. Relevant equations

Variables in equations: V = volume, P = pressure, C = Molar Specific Heat, n = moles, T = temperature, Q = heat

(I thought this was relevant but apparently it isn't and I don't understand why): Q = nC(delta T), with C being the molar specific heat constant for Nitrogen at constant pressure.

(actually relevant): for a process at constant pressure, Q = (change in internal energy) + P(delta V), which I can see is just the first law of thermodynamics.

Also, (internal energy) = (5/2)nRT for a diatomic gas

3. The attempt at a solution

This is kind of a request for clarification, rather than at solving the actual problem. Basically, right when I read the problem, I thought to myself that the first equation above (Q = nC(delta T)) would be the solution. It explicitly states in the book that the heat Q needed to raise the temperature of n moles of gas by delta T is given by that equation. However, that equation doesn't work. I eventually figured out that I'd have to use some equations on the next page, which are the other relevant equations that I posted, to solve the problem. So, I was able to get the solution. However, I still don't understand why the first equation I tried failed to work, and that bothers me. I am certain that I used the correct SI units. Any help?

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# Homework Help: Confusion regarding Thermodynamics - Molar Specific Heats for Gases

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