Thermodynamics Homework: Find Work Given Heat & Temp Change

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Homework Statement



When 1380 J of heat are added to one mole of an ideal monatomic gas, its temperature increases from 272 K to 275 K. Find the work done by the gas during this process.

Homework Equations



I assume \DeltaU = Q - W is the formula to use. But for some reason I'm just confused.

The Attempt at a Solution



I tried using 1380 = 275 - W, and got -1105. But that is not the correct answer.
 
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Can you relate \Delta U to \Delta T?
 
That's the problem, I don't understand how they relate. Is there a conversion from Kelvin to Joules? Or do I just use 3K = 1380J - W?
 
Check your book, notes, or reference for an equation of the internal energy (U) of an ideal gas.
 
Internal energy increases with increasing temperature, but the exact relation will depend on the type of gas. You should figure out how many degrees of freedom are present in a monatomic gas, then use equipartition of energy to express the internal energy as a function of temperature.
 
Robershky said:

Homework Statement



When 1380 J of heat are added to one mole of an ideal monatomic gas, its temperature increases from 272 K to 275 K. Find the work done by the gas during this process.

Homework Equations



I assume \DeltaU = Q - W is the formula to use. But for some reason I'm just confused.

The Attempt at a Solution



I tried using 1380 = 275 - W, and got -1105. But that is not the correct answer.
You are given Q and you can determine \Delta U = nC_v\Delta T. So it is just a matter of applying the first law to determine W.

AM
 

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