## Homework Problem 4f.7 7th edition

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

Eva Guillory 2E
Posts: 44
Joined: Fri Sep 28, 2018 12:22 am

### Homework Problem 4f.7 7th edition

I'm confused on 4F.7 a, because I keep getting 6.65 J*K^-1 rather than 6.80 J*K^-1.

Is this most likely due to rounding differences? If so, if anyone got 6.80 J*K^-1, can you mention what values you rounded to?

Oh, and for reference, here is what my problem looks like, which also lines up with the solutions manual:

ΔS = 1 mol * (5/2 * 8.134 J*K^-1*mol^-1) * ln ( 431 K / 310.8 K) = 6.65 J*K^-1

Chem_Mod
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### Re: Homework Problem 4f.7 7th edition

I just did the exact math that you provided on my calculator and got 6.8 J/K. Broken down into parts: ln(431/310.8)= ln(1.3867438867)=0.326958472, then multiply that by 8.314 = 2.718332733, then multiply that by 5 = 13.5916663665, then divide that by 2 = 6.7958318... so 6.8 J/K. If you round too early in your calculation that could be throwing your answer off, or if you're punching a single number in wrong that could cause it to change.