Question 1
Ethanol (C
2H
5OH) melts at -114 °C. The enthalpy of fusion is 5.02 kJ mol
-1. The specific heats of solid and liquid ethanol are 0.97 J g
-1 °C
-1 and 2.3 J g
-1 °C
-1, respectively. How much heat (kJ) is needed to convert 25.0 g of solid ethanol at -145 °C to liquid ethanol at -60 °C?
◦ -13.56
◦ 3859
◦ 9.96
◦ 8.88
◦ 6.58
Question 2
Ethyl chloride, C
2H
5Cl, is used as a local anesthetic. It works by cooling tissue as it vaporizes; its heat of vaporization is 26.4 kJ mol
-1. How much heat could be removed by 20.0 g of ethyl chloride?
◦ 528 kJ
◦ 341 kJ
◦ 8.18 kJ
◦ 3410 kJ