Compressing ideal gas isothermally, calc work

gcooke
Messages
5
Reaction score
0

Homework Statement



10 moles of an ideal gas are compressed isothermally and reversibly from 1 to 10 atmospheres at 300K. Determine the work done ON the gas.

Homework Equations



dw=-PdV
PV=nRT

The Attempt at a Solution



dT=0
T=300K
dP=10atm

calc dV from ideal gas law = 2.27e10 m^3

so now we have dV for work eqn, but P is not constant?

Thanks.
 
Last edited:
Physics news on Phys.org
As much as I don't like thermodynamics, it doesn't seem very complicated.
Start with claperyon equation nr. 1:
p1V1=nRT
which allows you to calculate the first volume.
Equation nr.2:
p2V2=nRT
allows you to calculate 2nd volume. Hence you've got your integrating limits.
Now, I wish I knew how to use TeX in here :/.
Anyway,
<br /> W=\int\limits_{v_1}^{v_2} pdV
As you mentioned, p is not constant, but you can, again, calculate it easily from clapeyron's equation:
pV=nRT. And then substitute p under integral with what you've got, integrate. Should get natural logarithm.
 
Last edited:
Thank you, irycio!
 
Thread 'Need help understanding this figure on energy levels'
This figure is from "Introduction to Quantum Mechanics" by Griffiths (3rd edition). It is available to download. It is from page 142. I am hoping the usual people on this site will give me a hand understanding what is going on in the figure. After the equation (4.50) it says "It is customary to introduce the principal quantum number, ##n##, which simply orders the allowed energies, starting with 1 for the ground state. (see the figure)" I still don't understand the figure :( Here is...
Thread 'Understanding how to "tack on" the time wiggle factor'
The last problem I posted on QM made it into advanced homework help, that is why I am putting it here. I am sorry for any hassle imposed on the moderators by myself. Part (a) is quite easy. We get $$\sigma_1 = 2\lambda, \mathbf{v}_1 = \begin{pmatrix} 0 \\ 0 \\ 1 \end{pmatrix} \sigma_2 = \lambda, \mathbf{v}_2 = \begin{pmatrix} 1/\sqrt{2} \\ 1/\sqrt{2} \\ 0 \end{pmatrix} \sigma_3 = -\lambda, \mathbf{v}_3 = \begin{pmatrix} 1/\sqrt{2} \\ -1/\sqrt{2} \\ 0 \end{pmatrix} $$ There are two ways...
Back
Top