1. Heat and Calorimetry
Energy Absorbed
SOLID
LIQUID
GAS
Energy Released

2. Heat = “transfer” of thermal energy
80oC
heat
20oC
It’s incorrect to say matter “contains” heat.
Matter “contains” KE
and PE.
Energy of Motion
Stored Energy
WS 1
(moving or vibrating)
(bonds & attractions)
Thermal Energy
Chemical Energy

3. heat heat matter WHY? Describe:
The same amount of heat is added to each container, but the temperature of the container with less water increases more.
Explain:
WS 1
Temp higher b/c T is a measure of _____ KE.
avg

4. + 4.18 J of heat specific heat capacity(c):
heat to change 1 gram by 1oC
WS 1
Different substances have different capacities for storing energy.
The water in food holds 4x the energy as an aluminum pan.
J of heat
c (water) = ________
4.18 J/goC

5. Specific Heat Capacities
Water absorbs/releases a lot of heat for a small ∆T
(change in temp)
Water has a high c !
Specific Heat Capacities
Substance
(J/goC)
Water (l)
4.18
Olive oil (l)
1.97
Aluminum (s)
0.900
Steel (iron) (s)
0.450
Copper (s)
0.385
Mercury (l)
0.140
Lead (s)
0.129
Gold (s)
Why?
1 g of water requires
more heat than
1 g of metal for
every 1oC change.
(higher specific heat capacity)

6. Substance (J/goC) 4.18 water has a high c !
Water (l)
4.18
Aluminum (s)
0.900
(demo)
Al metal atoms vibrate in place.
Water “soaks up” (stores) a lot of energy in
intramolecular movements and
intermolecular attractions (H-bonds)
without changing average KE (Temp)
water has a high c !
DEMO – burning dollar bill (50/50 mix of H2O/C2H5OH) DEMO – Boiling water in paper cup
vibrating
stretching
rotating

7. Calorimetry q = mcT Heat transferred can be measured and calculated.
given on exam
q = mcT
q = heat (J)
m = mass (g)
c = specific heat (J/goC)
(4.18 J/goC for water)
∆T = change in T
(Tfinal – Tinitial)
WS 1

8. Sample Calculation: q = mcT
How much heat is needed to warm 500 g of water from 25 oC to 100 oC?
q = mcT
c = 4.18 J/goC
q = (500)(4.18)(100 – 25)
q = 157,000 J

9. Quick Quiz!
Temperature is directly proportional to the _________ of a substance.
thermal energy
vibrational kinetic energy
average kinetic energy
total kinetic energy

10. Quick Quiz.
Heat is simply another word for _________.
temperature
internal energy
energy transferred from high to low temp
thermal energy transferred

11. Quick Quiz.
How much energy would it take to raise gram of liquid water from 20oC to 30oC?
4.18 J
20.9 J
41.8 J
209 J J

12. Quick Quiz.
How many joules would it take to raise grams of liquid water from 20oC to 30oC?
2090 J
418 J
209 J
41.8 J J