Download specific heat

Measuring Heat
1
Heat
Heat is defined as the flow of energy from
something warm to something cooler
because of the difference in their
temperatures
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Learning Check
A. When you touch ice,
1) heat is transferred from your hand to
the ice
2) coldness flows from the ice to your
hand
B. When you drink a hot cup of coffee, heat
is transferred from
1) your mouth to the coffee
2) the coffee to your mouth
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Specific Heat
 Why do some foods stay hot longer than
others?
 When you go to the beach, why is the sand
hot, but the water is cool on the same hot
day?
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Specific Heat Values
Specific heat is the amount of heat needed to
raise the temperature of 1 g of a substance by
1°C
J/g°C
water
4.18
aluminum
copper
silver
gold
0.90
0.39
0.24
0.13
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Learning Check
A. A substance with a large specific heat
1) heats up quickly
2) heats up slowly
B. When ocean water cools, the surrounding air
1) cools
2) warms 3) stays the same
C. Sand in the desert is hot in the day, and cool
at night. Sand must have a
1) high specific heat
2) low specific heat
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Measuring Heat Gained or Lost
Requires
 Grams of substance
 Temperature change T
 Specific heat of the substance
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Calculating Heat
q = mass x temp. change x specific heat
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Sample Heat Calculation
A hot-water bottle contains 750 g of water at
65°C. If the water cools to body temperature
(37°C), how much heat could be transferred
to sore muscles?
heat = mass x T
750 g x 28°C
x Sp. Ht. (H2O)
x 4.18 J
g°C
= 88,000 J
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