### 4F7

Posted: **Tue Feb 04, 2020 11:32 pm**

by **smurphy1D**

How would I solve for entropy change when i am only given the moles and two temperature calculations? Pressure and volume are assumed to be constant. I have converted them to K and found the delta T, but I am not sure what to do next.

### Re: 4F7

Posted: **Wed Feb 05, 2020 10:37 am**

by **Abigail Sanders 1E**

For this question we will use the equations (delta S)=(delta q)/T and q=nC(delta T). First, we will find the delta q. This is found by the equation (delta q)=nC(delta T). Then, we will divide this equation by T to find the entropy. This is equivalent to nC(delta T)/T. Then, to find the overall change overtime for S we will take the integral of this equation to get delta S=nC*ln(T2/T1). Using this equation you should be able to plug in moles and the two temperatures to find the change in entropy. Finally, we know C because it is an ideal gas at constant pressure which is equivalent to 5/2R. So, the final equation is S=n*(5/2)*R*ln(T2/T1)