Multiple Choice
Identify the
choice that best completes the statement or answers the question.
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1.
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What would likely happen if you were to touch the flask in which an endothermic
reaction were occurring?
a. | The flask would probably feel cooler than before the reaction
started. | b. | The flask would probably feel warmer than before the reaction
started. | c. | The flask would feel the same as before the reaction started. | d. | none of the
above |
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2.
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Which of the following is NOT a form of energy?
a. | light | c. | heat | b. | pressure | d. | electricity |
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3.
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If heat is released by a chemical system, an equal amount of heat will be
____.
a. | absorbed by the surroundings | c. | released by the
surroundings | b. | absorbed by the universe | d. | released by the universe |
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4.
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In an exothermic reaction, the energy stored in the chemical bonds of the
reactants is ____.
a. | equal to the energy stored in the bonds of the products | b. | greater than the
energy stored in the bonds of the products | c. | less than the energy stored in the bonds of the
products | d. | less than the heat released |
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5.
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What is the amount of heat required to raise the temperature of 200.0 g of
aluminum by 10  C? (specific heat of aluminum = 0.21  ) a. | 420 cal | c. | 42,000 cal | b. | 4200 cal | d. | 420,000 cal |
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6.
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How many kilocalories of heat are required to raise the temperature of 225 g of
aluminum from 20  C to 100  C? (specific
heat of aluminum = 0.21  ) a. | 0.59 kcal | c. | 85 kcal | b. | 3.8 kcal | d. | none of the
above |
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7.
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When 45 g of an alloy, at 25  C, are dropped into 100.0 g
of water, the alloy absorbs 956 J of heat. If the final temperature of the alloy is 37  C,
what is its specific heat? a. | 0.423  | c. | 9.88  | b. | 1.77  | d. | 48.8  |
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8.
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How can you describe the specific heat of olive oil if it takes approximately
420 J of heat to raise the temperature of 7 g of olive oil by 30  C? a. | greater than the specific heat of water | c. | equal to the specific heat of
water | b. | less than the specific heat of water | d. | Not enough information is
given. |
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9.
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Standard conditions of temperature and pressure for a thermochemical equation
are ____.
a. | 0 C and 101 kPa | c. | 0 C and 0
kPa | b. | 25 C and 101 kPa | d. | 25 C and 22.4
kPa |
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10.
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The specific heat of silver is 0.24  . How many joules of energy
are needed to warm 4.37 g of silver from 25.0  C to 27.5  C? a. | 2.62 J | c. | 45.5 J | b. | 0.14 J | d. | 0.022 J |
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11.
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Which of the following has the greatest heat capacity?
a. | 1000 g of water | c. | 1 g of water | b. | 1000 g of steel | d. | 1 g of steel |
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12.
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Which of the following substances has the highest specific heat?
a. | steel | c. | alcohol | b. | water | d. | chloroform |
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13.
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The amount of heat transferred from an object depends on which of the
following?
a. | the specific heat of the object | c. | the mass of the
object | b. | the initial temperature of the object | d. | all of the
above |
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14.
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On what principle does calorimetry depend?
a. | Hess's law | c. | law of enthalpy | b. | law of conservation of
energy | d. | law of multiple
proportions |
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15.
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A chunk of ice whose temperature is –20  C is added to
an insulated cup filled with water at 0  C. What happens in the cup? a. | The ice melts until it reaches the temperature of the water. | b. | The water cools
until it reaches the temperature of the ice. | c. | Some of the water freezes, so the chunk of ice
gets larger. | d. | none of the above |
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16.
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What is the standard heat of reaction for the following
reaction? Zn( s) + Cu   ( aq)  Zn  ( aq) +
Cu( s) (  H for Cu  =
+64.4 kJ/mol;  H for Zn 
= –152.4 kJ/mol) a. | 216.8 kJ released per mole | c. | 88.0 kJ absorbed per
mole | b. | 88.0 kJ released per mole | d. | 216.8 kJ absorbed per mole |
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17.
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Calculate  H for the following reaction. C  H  ( g) + H  ( g)
 C  H  ( g) (  H for C  H  ( g) = 52.5 kJ/mol;  H for C  H  ( g) = –84.7 kJ/mol) a. | –137.2 kJ | c. | 32.2 kJ | b. | –32.2 kJ | d. | 137.2 kJ |
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18.
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Calculate the energy released when 24.8 g Na  O reacts in
the following reaction. Na  O( s) + 2HI( g)  2NaI( s) + H  O( l)  H = –120.00 kcal a. | 0.207 kcal | c. | 48.0 kcal | b. | 2.42 kcal | d. | 3.00  10
kcal |
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19.
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To calculate the amount of heat absorbed as a substance melts, which of the
following information is NOT needed?
a. | the mass of the substance | c. | the change in
temperature | b. | the specific heat of the substance | d. | the density of the
sample |
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20.
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The  H is
____. a. | always negative | b. | always positive | c. | sometimes positive,
sometimes negative | d. | always 0 |
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21.
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When 1.0 g of solid NaOH (  H =
–445.1 kJ/mol) dissolves in 10 L of water, how much heat is released? a. | 445.1 kJ | c. | 11.1 J | b. | 405.1 kJ | d. | 11.1 kJ |
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22.
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When 10 g of diethyl ether is converted to vapor at its boiling point, about how
much heat is absorbed? (C  H  O,  H = 15.7 kJ/mol, boiling point: 34.6  C) a. | 2 kJ | c. | 0.2 kJ | b. | 2 J | d. | Not enough information is
given. |
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23.
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Hess's law ____.
a. | makes it possible to calculate  H for complicated
chemical reactions | b. | states that when you reverse a chemical
equation, you must change the sign of  H | c. | determines the way a
calorimeter works | d. | describes the vaporization of
solids |
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24.
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 H for the formation of
rust (Fe  O  ) is –826 kJ/mol. How
much energy is involved in the formation of 5 grams of rust? a. | 25.9 kJ | c. | 66 kJ | b. | 25.9 J | d. | 66 J |
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Short Answer
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25.
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The specific heat capacity of graphite is 0.71  . Calculate
the energy required to raise the temperature of 750 g of graphite by 160  C.
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26.
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Suppose a substance has a heat of fusion equal to 45 cal/g and a specific heat
of 0.75  in the liquid state. If 5.0 kcal of heat are
applied to a 50-g sample of the substance at a temperature of 24  C, what will
its new temperature be? What state will the sample be in? (melting point of the substance = 27  C; specific heat of the solid = 0.48  ; boiling point of the
substance = 700  C)
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27.
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Consider a 67-g chunk of ice (  H =
6.0 kJ/mol) in a beaker immersed in a water bath. To produce just enough heat to melt the ice, how
many moles of solid NaOH (  H =
–445.1 kJ/mol) must you dissolve in the water bath?
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28.
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29.
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A 55.0-g piece of copper wire is heated, and the temperature of the wire changes
from 19.0  C to 86.0  C. The amount
of heat absorbed is 343 cal. What is the specific heat of copper?
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