Recent content by Sabian

You are rigut, it's w^4 but the result of the integral is right anyway. So I should divide by the integral of dN_w^e over all speeds, which I think it is: \frac {\sigma N}{sqrt \pi V c^3} . \frac {c^4}{2} = \frac {\sigma N c}{2 \sqrt \pi V} The I have \frac { \frac {\sigma N } {\sqrt \pi...

Homework Statement Find the mean speed of the molecules escaping through a hole of area \sigma. The vessel has volume V and the molecules mass m.Homework Equations dN_w^e = \frac {dA}{4V} w \frac{dN_w}{dw} dw w is the speed. dN_w = \frac {4N}{\sqrt \pi c^3} w^2 \exp {\frac {-w^2}{c^2} }dw...

Good catch on the molar dependance, hadn't looked at that. The excercise I was looking at says \mu (P,T,n) . I have some doubts on that being on purpose, but anyway... ------------------ Then I have G = n c_v T + U_0 - T \left (S_0 + n c_v ln (T) + nR ln \left ( \frac{RT}{P} \right ) \right...

Homework Statement Basically, find the chemical potential of an ideal gas knowing its heat capacities.Homework Equations P V = n R T \ \ \ \ (1) U = n c_V T + U_0 \ \ \ \ (2) S = S_0 + n c_V ln (T) + nR ln (V) = S_0 + n c_V ln (T) + nR ln \left ( \frac{nRT}{P} \right ) \ \ \ \ (3) \mu = \left...

You are right, I don't know why I try to make it so complicated. Just for the exercise to be complete if someone looks for this: - \frac {C_P dT_C}{C_P dT_H} = \frac {T_C}{T_C} \Longrightarrow \frac {dT_C}{T_C} = - \frac {dT_H}{T_H} Then integrating that condition through the whole process...

I'll start again to be more clear on the notation First law applied to the engine: \delta Q + \delta W_{on} = 0 \delta Q_H + \delta Q_C = - \delta W_{on} , where the work here is the on done ON the engine, so, changing for the work done BY it and considering absolute values of heat...

Thanks for such quick answers man. I'm quitting study now, it's beer time :P, but tomorrow I'll look into it and write what I get.

Thanks for your reply. Which information am I adding that way? The first law is already implied. I think I have to incorporate the fact that it's not an ordinary engine, but a Carnot one, which won't come up that way. I thought something like \frac {\delta W}{\delta Q_H} = \frac {|Q_H| -...

Homework Statement It's basically the classic problem I've seen here a lot. There are two bodies, both with equal heat capacity (C_P), one at temperature T_1 and the other at T_2. They exchange heat using an infinitesimal-reversible Carnot Engine, which will work until thermal equilibrium is...

I could figure it out, thanks man, really.

I know it's rude to bump threads, but does anybody have the time and knowledge to help me?

Homework Statement One body of constant pressure heat capacity C_P at temperature T_i it's placed in contact with a thermal reservoir at a higher temperature Tf. Pressure is kept constant until the body achieves equilibrium with the reservoir. a) Show that the variation in the entropy of the...

I think it's a bit late to answer the original poster but I'll write how I ended up as an undergrad student of Geophysics myself. Luckily it's not a long story, in high school although I liked almost everything, the only things I would keep thinking out of the classroom where Maths...