Change in internal engergy of a monatomic ideal gas

[alexthelion]

Homework Statement

A monatomic ideal gas expands from 1.00 meters cubed to 2.50 meters cubed at a constant pressure of 2.00 x 10^5 Pa. Find the change in the internal energy of the gas.

Homework Equations

$$\Delta$$U = Q + W

The Attempt at a Solution

Well, I know how to find work, which is -P$$\Delta$$V

But I'm having trouble finding the energy transferred into the system by heat, or Q, because the problem does not give a specific value for it.

I would much appreciate it if someone could give me some pointers as to how to find Q.

 

[kuruman]

How is Q related the the specific heat at constant pressure?

 

[alexthelion]

I don't exactly know, I do know that $$\Delta$$U = 3/2nR$$\Delta$$T for a monatomic gas, where the molar specific heat is given by Cv = 3/2R

 

[kuruman]

If you know C_V, then C_p = C_V + R. Also at constant pressure Q = n C_pΔT. Now you can put it together.

 

[alexthelion]

Aha, thanks for the help! I got it.