Question

How much energy (in kilojoules) is released when 15.2g of steam at 114.5∘C is condensed to give liquid water at 63.5∘C? The heat of vaporization of liquid water is 40.67 kJ/mol, and the molar heat capacity is 75.3 J/(K⋅mol) for the liquid and 33.6 J/(K⋅mol) for the vapor.

Answer 1

q1 = heat released in moving T of steam from 114.5 C to 100 C.
q1 = mass steam x specific heat steam x (Tfinal-Tinitial)

q2 = heat released by condensing steam at 100 C to liquid water at 100 C.
q2 = mass steam x heat vaporization/condensation

q3 = heat released by cooling from 100 C to 63.5 C.
q3 = mass H2O x specific heat H2O x (Tfinal-initial)

Total = q1 + q2 + q3.
Note: Make sure your units for mass and specific heat are the same; i.e., if you use mass in grams then you want specific heat in J/g. If you use specific heat in J/mol, you must use mass in mols.

Answer 2

I keep getting 5651.072 kJ.