EXERCISE 10-1 Energy Changes
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1
The specific heat of water is 4.184 J/g-
o
C. How many Joules does it take to heat 5.0 grams of water from 15
o
C to 45
o
C?
9.4x10
2
J
1.5x10
2
J
3.1x10
2
J
6.3x10
2
J
None of the previous answers.
2
The specific heat of iron is 0.449 J/g-
o
C. How many Joules does it take to heat 5.0 grams of iron from 15
o
C to 45
o
C?
67 J
1.0x10
2
J
6.3x10
2
J
34 J
None of the previous answers.
3
What is the ratio of the temperature change for iron to water if the same amount of heat is transferred to the same mass of each substance?
0.107
1.00
9.32
None of the previous answers.
4
Calculate the predicted temperature change if 125 calories are transfered to 25 g of water.
1.2
o
C
5.0
o
C
21
o
C
None of the previous answers.
5
Calculate the specific heat of a metal if 225 Joules warms up 15.0 g warms of the metal from 22.0
o
C to 61.0
o
C.
0.246 J/g-
o
C
0.682 J/g-
o
C
0.385 J/g-
o
C
None of the previous answers.
6
An approximate relation attributed to Dulong and Petit is that division of 25 by the specific heat (in J/g-
o
C) gives the atomic mass. Which of the metals below could be the metal in problem #5?
Pb
Cu
Sn
Al
None of the previous answers.
7
The heat of fusion of ice (the energy required to melt 1.00 gram of ice) is 6.01 kJ/mol. How much heat (in Joules) is required to melt 3.00 grams of ice at 0.0
o
C and raise the temperature of the water to 15.0
o
C?
1.82x10
5
J
1.19x10
3
J
1.89x10
2
J
None of the previous answers.
8
The melting point of a substance is the same as its:
boiling point
sublimation point
freezing point
condensation point.
None of the previous answers.
9
Sublimation is:
a phase change directly from solid to gas
a phase change from liquid to solid
a phase change from solid to liquid
the opposite of distillation
None of the previous answers.
10
Boiling occurs:
at 100
o
C.
below the melting point.
when the vapor pressure equals the confining pressure.
None of the previous answers.
11
A 25.0 g piece of aluminum at 100.0
o
C is immersed in 20.0 g of water originally at 22.0
o
C. The resulting temperature of the mixture is 38.5
o
C. Assuming the calorimetry constant is zero, calculate the specific heat of aluminum in J/g
.o
C.
1.2 J/g-
o
C
4.2 J/g-
o
C
0.90 J/g-
o
C
None of the previous answers.
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