# Thermal Equilibrium of steam

## Main Question or Discussion Point

Hi

Just wondering if I could have a bit of help on this question. Thanks in advance!

3) 100 g of steam at 150_C and 1 kg of water at 20_C are placed together inside
an insulated volume. The specic heat of steam is 2.02x10^3J kg_1K_1, that
of water is 4.19 x10^3 J kg_1K_1 and the latent heat of evaporation of water is
226x10^6 J kg_1.

a) Once the two fluids have come into thermal equilibrium what is left - water or
steam?

b) Calculate the final temperature of the system.

c) Is the net change in the internal energy of the system positive, negative or
zero?

d) Calculate the increase in entropy of the system.

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tiny-tim
Homework Helper
Welcome to PF!

Hi Crocodile! Welcome to PF!
Just wondering if I could have a bit of help on this question.
Yes, but only a bit

Show us what you've tried, and where you're stuck, and then we'll know how to help!

Thanks for the welcome! Well....sorry to sound slightly stupid, but this topic isn't my forte so I haven't really got a clue where to start! Any help at all would be appreciated.

Well, for part b I may have an idea - whether its viable or not I'm not sure... My thoughts are that we know that the total energy of the system must remain constant. Therefore would it be possible to put the specific heat capacity equation of both cases equal to eachother? I.e. the dQ would be the same for both the steam and the water.

Thanks.

tiny-tim