Question

How much heat is required to heat 9.61g of ethanol (CH3CH2OH) from 24.10C to 67.30C?

Answer 1

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: