How to Calculate Entropy and Enthalpy in a Thermodynamics Problem

[Clara Chung]

Homework Statement

Homework Equations

The Attempt at a Solution

I don't know how to do part c and part d. The answers are 1223 Jkg-1K-1 , 213.3 K respectively. (Answer for enthalpy not given)

It seems that they get the answer of part c by dividing 334kJ by 273 and multiply by 100 seconds.
However, Isn't that ds = dQ/T ? Change of Q in 100 seconds is 25130 J by part a, so isn't the entropy 25130/273 = 92.05 ? For the enthalpy, isn't it 25130J?

For part d, my answer is not accurate, my idea is as follow:
C(400)(T-213)=C(1)(273-T)
I got T=213.149K , why am I wrong?

Thank you so much

 

[Chestermiller]

Your assessment seems totally correct to me.

 

[Clara Chung]

Your assessment seems totally correct to me.

Thanks for pointing that out. Why am I wrong?

 

[Chestermiller]

Thanks for pointing that out. Why am I wrong?

I don't think you are wrong.

 

[TSny]

For part d, my answer is not accurate, my idea is as follow:
C(400)(T-213)=C(1)(273-T)

The only thing that I see that is wrong is using 1 kg for the mass on the right side of the equation above. But, if you use the correct amount of mass, it won't really make much difference in the answer.