Problem 2.6: How much energy is required to a heat 1 pound
From Chapter 2 Problem Set. Level 2: Applied Thinking.
Question
How much energy is required to (a) heat 1 pound of water from 72°F to 212°F, and (b) completely vaporize that same pound of water at 212°F? How many times more energy does vaporization require than heating the water from 72°F to 212°F?
Answer
Show answer
(a) Sensible: 1 lb × 1.0 × (212 − 72) = 140 BTU. (b) Latent: 1 lb × 970 BTU/lb = 970 BTU. Vaporization requires 970/140 = 6.9 times more energy than heating to the boiling point.