Answer:
a.)
To warm the liquid from 35°C to 78°C:
(2.3 J/g-K) x (42.0 g) x (78 - 35) = 4154 J
To vaporize the liquid at 78°C:
(38.56 kJ/mol) x (42.0 g C2H5OH / 46.06867 g C2H5OH/mol) = 35.154 kJ
Total:
4.154 kJ + 35.154 kJ = 39.3 kJ
b.)
To warm the solid from -155°C to -114°C:
(0.97 J/g-K) x (42.0 g) x (-114°C - (-155°C)) = 1670 J
To melt the solid at -114°C:
(5.02 kJ/mol) x (42.0 g C2H5OH / 46.06867 g C2H5OH/mol) = 4.5766 kJ
To warm the liquid from -114°C to 78°C:
(2.3 J/g-K) x (42.0 g) x (78 - (-114)) = 18547 J
To vaporize the liquid at 78°C:
35.154 kJ (as in part a.)
Total:
1.670 kJ + 4.5766 kJ + 18.547 kJ + 35.154 kJ = 59.9 kJ
Explanation:
