
#1
Mar1709, 11:52 AM

P: 21

1. The problem statement, all variables and given/known data
1 Kg of water is heated at 0 degree C is brought into contact with a large heat reservoir at 100 degrees C. When the water has reached 100 degrees C, what has been the change in entropy of the water? And of the heat reservoir ? what has been the change in the entire system consisting of both water and the heat reservoir? 2. Relevant equations [tex]\Delta[/tex]S_{w} = mcln(T_{f}/T_{i}) where m = mass of water c = specific heat capacity of water ( 4186 J/K) T_{f} = final common temperature of water and the reservoir T_{i} = initial temperature of water (and also reservoir for part b of the question) 3. The attempt at a solution The application of formula above gave me answer for entropy change in water but not for reservoir and the whole system. Some help anticipated. 



#2
Mar1709, 01:47 PM

Sci Advisor
HW Helper
P: 6,593

To determine the change in entropy of the reservoir just use the definition of entropy: [tex]\Delta S = \Delta Q/T[/tex] Since T does not change, this is simply a matter of looking at the heat flow to/from the reservoir. Be careful about the signs:  is heat flow out; + is heat flow into the reservoir. AM 



#3
Mar1709, 05:18 PM

P: 72

consider the heat flow of the system. Negative of heat gained by 1 kg of water is the heat lost by the reservoir. From that calculate the change in entropy. Keep track of the signs.
Good luck 


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