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morrobay
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Homework Statement
100g of lead, specific heat .0345 cal/g/C at 100 C is mixed with 200 g of water at 20 C.
Find the difference in entropy of system at end from value before mixing.
Note: I think the book has wrong answer of 1.42 cal/K
Homework Equations
Before mixing entropy for water = 4000 c/293 K = 13.65 c/K
Entropy for lead = 100g * .0345 c/g/C * 100C = 345 c/373K = .925 c/K
Total before mixing = 14.57c/K
The Attempt at a Solution
The lead loses 276 calories going from 100 C to 20 C
So now the water temp is 4276 c/ 200g * 1c/g/C = 294.38K entropy =
4276 c/ 294.38K=14.52c/K
For the mixed in lead = 69 c/.0345 c/g /C= 2000gC /100g= 293K S = 69c/293k = .23c/K
So total after mixing = 14.75c/K
ΔS = 14.75c/K - 14.57c/K = .18c/K
I think the book got the wrong answer with : 4345 c/293 K = 14.82 c/K
And 345 c/293K = 1.177 c/K for total 15.99 c/K - 14.57c/K = 1.42 c/K
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