How much energy (in kilojoules) is released when 21.0 of ethanol vapor at 94.5 is cooled to -19.0?

Answer 1

You need to look up the boiling point temperature and the freezing point T, then use these general formulas.

q1 = mass ethanol vapor x specific heat ethanol vapor x (Tfinal-Tinitial) for all temperatures above the boiling point.

q2 = mass ethanol x heat vporization at the boiling point.

q3 = mass ethanol liquid x specific heat ethanol liquid x (Tfinal-Tinitial) for temperatures from the boiling point to its freezing point.

q4 = mass ethanol liquid x heat fusiion at the freezing point.
Total Q = q1 + q2 + q3 + q4.