1. Weather Dynamics: Energy and Water Ch 13
Weather Dynamics: Energy and Water Ch 13.2 (p ) Calculating Specific Heat Capacity

2. Specific heat capacity Heat of vaporization Heat of fusion
Temperatures of the oceans and very large lakes are relatively constant for several reasons:
Specific heat capacity
Heat of vaporization
Heat of fusion
We will examine Specific Heat Capacity today.

3. Specific Heat Capacity
The amount of heat required to raise the
temperature of 1 gram of a substance by 1°C.

4. Specific Heat Capacity (c)
is the amount of heat
(Q) Measured in Joules (J)
taken in or given off to change the temperature
(ΔT)
of one gram of a substance (mass)
(m) Measured in grams (g)
by one degree Celsius
( °C ).

5. Specific heat capacity is the number of joules (J) per
So…
Specific heat capacity is the number of joules (J) per
gram
times degree
celsius.
The unit for Specific heat capacity is J/g°C

6. you can calculate the amount of heat (Q)
Using the formula
Q = mcΔT
you can calculate the amount of heat
(Q)
required to raise the temperature of a mass of a substance
(m)
by a given temperature change
(ΔT).

7. Substances and their calculated Specific Heat Capacities
Specific Heat Capacity (J/gºC)
Water (pure)
4.18
This means that it takes 4.18 Joules of heat energy to raise the temperature of 1 gram of pure water by 1 degree celsius.

8. Substances and their calculated Specific Heat Capacities
SHC (J/gºC)
Water (pure)
4.18
Sea water
3.89
Dry air
1.00
Pure water has a higher Specific Heat Capacity than sea water. This means that it takes more energy (joules) to raise the temperature of pure water than it takes to raise the temperature of sea water.

9. Wet mud
2.51
Ethanol (rubbing alcohol)
2.46
Limestone
0.92
Brick
0.84
Granite
0.79
Lead
0.13
Copper
0.39
Iron
0.45
Aluminum
0.90
Heavy oil
2.1
Ice

10. 1 gram of ethanol when each absorbs 10 Joules of thermal energy.
Practice Question
Using the formula Q = mcΔT compare the increase in the temperature of 1 gram of water with the increase in the temperature of
1 gram of ethanol when each absorbs 10 Joules of thermal energy.

11. Solution For water Q = mcΔT 10 J = 1.0 g x 4.18 J x ΔT gºC 10 J = ΔT
ΔT = 2.4ºC

12. For ethanol
Q = mcΔT
10 J = 1.0 g x 2.46 J x ΔT
gºC
10 J = ΔT
2.46 ºC
ΔT = 4.1º C

13. Paraphrase of the Solution
 When1.0 g of water absorbs 10 J of energy,
then its temperature increases by 2.4º C.
 When 1.0 g of ethanol absorbs 10 J of energy
then its temperature increases by 4.1ºC.
Therefore, the temperature of ethanol increases
more than the temperature of water under the
same conditions.