1. Latent Heat
Energy is required for a material to change phase, even though its temperature is not changing.
(m) Mass of
the object
(L) Latent heat
of the fusion or
vaporization
(Q) Thermal
energy added

2. Heat of fusion, Lf: heat required to change 1
Heat of fusion, Lf: heat required to change 1.0 kg of material from solid to liquid
Heat of vaporization, Lv: heat required to change 1.0 kg of material from liquid to vapor
Chapter 14 - Page 392
Heat 14 (13 of 32)

3. Latent Heat Q2= mLf Q4= mLv 3.33 x 105 J 22.6 x 105 J 1 kg Ice -50 oC50
100
150
Q1= mcIDt
1.05 x 105 J
Q3= mcWDt
4.19 x 105 J
Q5= mcSDt
1.01 x 105 J
Specific Heat
Specific Heat
Specific Heat

4. Heat required to convert 1 kg of ice
at -50 oC to steam at 150 oC
Q1 = 1.05 x 105 J
Q2 = 3.33 x 105 J
Q3 = 4.19 x 105 J
Q4 = 22.6 x 105 J
Q5 = 1.01 x 105 J
3.22 x 106 J

5. Problem:
A large block of ice at 0 oC has a hole chipped in it, and 400 g of aluminum pellets at a temperature of 30 oC are poured into the hole. How much of the ice melts?

6. Problem: 100 W A heating coil is placed in a thermally insulated tank
of negligible heat capacity. The tank contains 0.10 kg
of water and kg of ice, both initially at 0 °C. The
coil delivers energy at a rate of 100 W.

7. Find the heat transferred to the
water and ice by the heating coil
in the first 10 s.

8. Find the time required to melt
all of the ice

9. After the ice is melted find the
additional time required to bring
the water to a boil.