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tdusffx

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equilibrium. What is the change in entropy in cal/K of the system? (Lf = 80cal/g)

a. 300

b. 100

c. 200

d. 50

e. 25

Qcold = -Qhot

Mw*Cw*dT + Lf*Mw = -Mw*Cw*dT + Mw*Lv

All has Mw in common, therefore it should cancel out

Cw*dT + Lf*Mw = -Cw*dT + Mw*Lv

(1cal/g)(Tf - 0) + 80cal/g = -(1cal/g)(Tf-100) + 540cal/g;

I converted the latent heat of vaporation (2.26x10^6J/kg)*(1/4186cal*kg/J*g) ~

540cal/g

after equating the two sides, I got 280C for Tf

My answer for Tf doesn't seem reasonable because the Final Temp should be in between

0-100C

Anyways, My other problem is getting the dQ

I have no idea how to get it...or maybe I do..when it doubt I just ask people out!

dS = dQ/T

if my T is right then just finding dQ problem

Thanks in advance folks.