Chemistry 51 - Fundamentals of Chemistry » Fall 2021 » Chapter 7 Homework

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Question #1
Heat, work, and energy all have the same units.
A.   TRUE
B.   FALSE
Question #2
A 1.265 kilocalorie when expressed in joules is 5293 J.
A.   FALSE
B.   TRUE
Question #3
Heat always flows from a body with higher temperature to a body with lower temperature.
A.   TRUE
B.   FALSE
Question #4
The quantity of heat is transferred when a 565 g block of aluminum metal is cooled from 243°C to 100°C is 17400 cal. The specific heat capacity of aluminum is 0.900 J/g oC.
A.   FALSE
B.   TRUE
Question #5
The increase of the temperature of a substance weighing 1000 g when 1000 cal of energy is transferred to it is an example of an isothermal process.
A.   TRUE
B.   FALSE
Question #6
Nutritional energies are usually expressed as _____.
A.   kJ
B.   Cal
C.   joule
D.   watt
E.   cal
Question #7
The energy content of a bar of chocolate is 120.0 Cal. What is the energy content in kJ?
A.   502,100
B.   120
C.   502.1
D.   28.68
E.   120,000
Question #8
A specimen weighing 100.0 g is heated from 30.00°C to 63.30°C. If the quantity of heat transferred is 5834 cal, determine the specific heat of the specimen.
A.   17.25 cal/ g·°C
B.   1.572 cal/ g·°C
C.   1.752 cal/ g·°C
D.   1.257 cal/ g·°C
E.   12.75 cal/ g·°C
Question #9
What quantity of heat is transferred when a 250.0 g block of aluminum is heated from 25.00°C to 73.30°C? (Hint: The specific heat of aluminum = 0.2150 cal/g·°C.)
A.   56160 cal
B.   2596 cal
C.   1.110 cal
D.   8986 cal
E.   1298 cal
Question #10
At what temperature can water exist as both a liquid and a gas?
A.   –4°C
B.   4°C
C.   100°C
D.   0°C
E.   10°C
Question #11
How much energy is needed to melt 87.6 g of Au at its melting point of 1,064°C? (Hint: The heat of fusion of Au = 15.3 cal/g.)
A.   14400 cal
B.   670 kcal
C.   12.1kJ
D.   2.80 kJ
E.   1340 cal
Question #12
What is the heat of fusion of iron in calories per mole?
A.   4.53 × 100 cal/mol
B.   4.53 × 102 kcal/mol
C.   5.34 × 104 cal/mol
D.   4.35 × 103 kcal/mol
E.   3.54 × 103 cal/mol
Question #13
What is the process by which a substance forms vapor directly from the liquid state?
A.   Melting
B.   Sublimation
C.   Vaporization
D.   Condensation
E.   Fusion
Question #14
Which of the following statements is true for the bonding of atoms?
A.   Individual atoms have higher amounts of energy than when in a compound.
B.   The energy of a compound is equal to the energies of the atoms which make up the compound.
C.   When a compound disintegrates there is a release of energy which equals the difference in energy between individual atoms.
D.   The formation of a compound naturally, from individual atoms, requires external energy.
E.   The energy of the individual atoms is lower than the energy of the compound.
Question #15
A serving of Chicken A La King has 235 kcal. If the serving has 11 g of carbohydrates and 12 g of fat, about how many grams of protein are in the serving?
A.   7.0 g
B.   13 g
C.   27 g
D.   21 g
E.   11 g
Question #16
The reaction between sodium metal and H2O gives off heat. This type of reaction is called an _____ reaction.
A.   exothermic
B.   energy requiring
C.   endothermic
D.   energy-less
E.   isothermal
Question #17
The reaction with which dietary component gives off the most energy?
A.   fiber
B.   carbohydrates
C.   sugar
D.   protein
E.   fats
Question #18
4 Cal is equal to _______ joules.
A.   16736
B.   176736
C.   16376
D.   17663
Question #19
The phase change wherein a solid goes directly to a gas is called _______.
A.   evaporation fusion
B.   melting
C.   sublimation
Question #20
The temperature change when 4460 cal of heat is used to melt 55.8 grams of ice is _______.
A.   4
B.   3
C.   0
D.   6

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