## 9.15 confusion

Volume: $\Delta S = nR\ln \frac{V_{2}}{V_{1}}$
Temperature: $\Delta S = nC\ln \frac{T_{2}}{T_{1}}$

Allison Young 1K
Posts: 23
Joined: Fri Sep 29, 2017 7:06 am

### 9.15 confusion

9.15 : Use data in Table 8.3 or Appendix 2A to calculate the entropy change for (a) the freezing of 1.00 mol H2O(l) at 0.00 \$C; (b) the vaporization of 50.0 g of ethanol, C2H5OH, at 351.5 K.

In the solution for part (b), delta H is found by multiplying the # of moles of C2H5OH by 43.5 kJ/mol. I could not find the value 43.5 kJ/mol in the book so I am confused as to what that is & where to get that value from.

Curtis Wong 2D
Posts: 62
Joined: Sat Jul 22, 2017 3:00 am

### Re: 9.15 confusion

Since we're calculating phase change you can find the value of 43.5 on page 284, where it lists all the values of the standard enthalpies of phase changes.

Allison Young 1K
Posts: 23
Joined: Fri Sep 29, 2017 7:06 am

### Re: 9.15 confusion

Ahhh so I'm just blind lol. Thank you!