Chemistry - Thermodynamics - II Question with Solution | TestHub
ChemistryThermodynamics - IICalculation of DSMedium2 minQB
ChemistryMediumsingle choice
A piece of alloy weighing 4 kg and at a temperature of 800 K is placed in 4 kg of water at 300 K. If the specific heat capacity of water is 1.0 cal/K-g and that of alloy is 4 cal/K-g, the ΔSmix is (ln 2 = 0.7, ln 3 = 1.1, ln 7 = 1.95)
Options:
Answer:
C
Solution:
Heat capacities: alloy 4000 g × 4 = 16000 cal/K, water 4000 g × 1 = 4000 cal/K. Equilibrium temperature Tf = (16000 × 800 + 4000 × 300)/20000 = 700 K. ΔS = 16000 ln(700/800) + 4000 ln(700/300) = 16000 ln(7/8) + 4000 ln(7/3) = 16000(1.95 − 2.1) + 4000(1.95 − 1.1) = −2400 + 3400 = +1000 cal/K = +1.0 kcal/K. Matches (c).
Stream:JEESubject:ChemistryTopic:Thermodynamics - IISubtopic:Calculation of DS
⏱ 2mℹ️ Source: QB
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