- #1
vetgirl1990
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Homework Statement
A 20 kg sample of mercury is completely solidified and liberates 231.6 kJ of energy. What is the original temperature of the mercury? (The melting point of mercury is 234K, the heat of fusion of mercury is 11.3 kJ/kg, and the specific heat of mercury is 140 J/kg•K.) . What is the mercury entropy change ΔS in this process?
Homework Equations
q=mcΔT
ΔS = ∫Q/dt
For phase change: ΔS = (latent heat)m / T(of phase change)
The Attempt at a Solution
I found the original temperature of mercury to be 236K. A pretty straightforward calorimetric problem.
But having trouble finding the entropy change.
ΔS = mCln(Tf/Ti) + Lfusion*m/Tfreezing point
= (20)(0.14)ln(234/236) + (11.3)(20)/234
= 941.98J/K
The answer is -19819J/K