Ethanol (C 2 H 5 OH) melts at -114°C. The enthalpy of fusion is 5.02 kJ/mol. The
ID: 526232 • Letter: E
Question
Ethanol (C2H5OH) melts at -114°C. The enthalpy of fusion is 5.02 kJ/mol. The specific heats of solid and liquid ethanol are 0.97 J/gK and 2.3 J/gK, respectively. How much heat (kJ) is needed to convert 25.0 g of solid ethanol at -135°C to liquid ethanol at -50°C?
Ethanol (C2H5OH) melts at -114°C. The enthalpy of fusion is 5.02 kJ/mol. The specific heats of solid and liquid ethanol are 0.97 J/gK and 2.3 J/gK, respectively. How much heat (kJ) is needed to convert 25.0 g of solid ethanol at -135°C to liquid ethanol at -50°C?
-12.7 kJ 4192 kJ 9.21 kJ 207.3 kJ 6.91 kJExplanation / Answer
Moles of ethanol= mass/ molar mass= 25/ 46=0.5434
Total heat to be supplied= sensbile heat of solid + latent heatof fusion ( at constant temperature of -114 deg.c)+ sensible heat of liquid = 509.25/1000 Kj + 2.73+3680/1000 Kj=6.92 KJ ( E is correct)
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