Download Specific Heat

Thermochemistry
Specific Heat
Specific Heat 
Amount of heat it takes to raise 1g of
How easy or hard an object
a substance by 1°C
is to heat up – how fast does
it absorb heat energy


Metals have a low specific heat
Water has a high specific heat
Learning Check
1. On a sunny day, the concrete deck around
an outdoor swimming pool becomes hot,
while the water stays cool. This is because…
A. The deck has a higher specific heat than the
water
B. The deck has a lower specific heat then the
water
C. Both objects have the same specific heat
Learning Check
2. Two objects are sitting next to each other
in the sunlight. Object A gets hotter than
object B.
A. Object A has a lower specific heat than
object B
B. Object A has a higher specific heat than
object B
C. Both objects have the same specific heat
Specific Heat of Water
Matches definition: Amount of heat it takes to raise
1g of a substance by 1°C
4.18 J/g × °C
or
1 cal/g × °C
Formula for Specific Heat
q = mc ΔT
q = amount of heat – measured in cal or J
m = mass – measured in g
C = specific heat – units are J/g x °C or
cal/g x °C
ΔT = change in temp – measured in °C
Specific Heat Problems:
1. Aluminum has a specific heat of 0.9020 J/g × °C. How
much heat is lost when a piece of aluminum with a
mass of 23.984 g cools from a temperature of 415.0°C
to a temperature of 22.0°C?
2. 850 calories of heat are applied to a 250 g sample of
liquid water with an initial temperature of 13.0 °C.
Find: a) the change in temperature and
b) the final temperature.
(remember, the specific heat of liquid water, in calories, is
1.00 cal/g x °C.)
Specific Heat Problems:
3. The temperature of a sample of water
increases by 69.5 °C when 24,500 J are
applied. The specific heat of liquid water is
4.18 J/g x °C. What is the mass of the sample
of water?
4. When 34,700 J of heat are applied to a 350 g
sample of an unknown material the temperature
rises from 22.0°C to 173.0°C. What must be
the specific heat of this material?