Practice!

Sample Problem

How much heat will it take to heat 10.0 kg of water from 283 K to 383 K? The boiling point of water is 373 K. The latent heat of vaporization of water is 2260 kJ/kg, and the specific heat of water is 4.2 kJ/kgK.

Solution

We will use the formulas Q1 = mcΔT, and Q2 = mL, and then add them, Q1 + Q2 = Qtotal. When we plug in our known values we get that Q1 = (10) (4.2) (100) = 4200, and Q2 = (10.0) (2260) = 22,600. When we add them together we get Qtotal = 26800 kJ.