Question

100 gm of steam at 100 degree celcius is converted into steam at the same temperature. Calculate the change in entropy, Given Latent heat of steam =536cal/gm * Answers: 1) 140cal/K 2) 143.69 cal/degree celcius 3) 143.69 cal/K 4) None of the above

Answer 1

Answer:

Let the mixture become water at T

o

C at steady state.

To convert steam at 100

o

C to water at T

o

C

Q=1×540+1×1×(100−T)

Similarly, to convert 1 g of ice to water at T C

Q=1×80+1×1×(T−0)

Since, both these heats should be the same,

540+100−T=80+T

⟹2T=560

⟹T=280

o

C

Since, this is not a possible value of T hence water wont exist and it will be precisely steam at 100

o

C