6 CHEM 100 Sample Problems for Chapter SAMPLE TEST CHAPTER 6

CHEM 100 Sample Problems for Chapter 6
SAMPLE TEST CHAPTER 6
A.-224.4 kJ
C. +149.6 kJ
1.
A process in which heat flows from the
reaction system into the surroundings is
called,
A. one in which q > 0. B. endothermic
C. exothermic
D. caloric
8. The heat of vaporization of mercury is 59.4
kJ/mole at its boiling point of 357°C. Determine
the heat required to vaporize 25.0 g of mercury at
its boiling point.
A. 0.749 kJ B. 2.38 kJ C. 4.16 kJ D. 7.40 kJ
9. Which of the following substances has a heat of
formation equal to zero at 25°C and 1 atm?
A. H2O(g) B. Na(g) C. O2(g) D. Cl-(aq)
2. The specific heat of iron is greater than that of
copper. Suppose equal masses of these two metals,
both initially at 25°C, are added to a beaker of
boiling water (100.0°C).
A. The final temperature of the iron sample will be
greater than that for copper.
B. The final temperature of the copper sample will
be
greater than that for iron.
C. The final temperatures will depend on the rate of
heating.
D. Both iron and copper samples will be at the same
final temperature.
3. A reaction caused the temperature of 28.00
grams of water (specific heat = 4.18 J/g°C) to rise
from 25.00°C to 26.48°C. The value of "q" for this
reaction is;
A.
-9.62 J B. -32.1 kJ C. -124 J D. -173 J
4. If 2.17 kJ of heat are used to warm 2.0 x 102g of
air initially at 20.0°C, determine the final
temperature of the air. The specific heat of air is
1.0 J/g°C.
A. 11°C
B. 21°C
C. 31°C
D. 41°C
5. When 5.8 g of potassium persulfate, K2S2O8,
dissolve in 48.6 g of water (specific heat = 4.18
J/g°C),the temperature is raised from 22.6°C to
29.0°C; how much energy is released by the
dissolution of this sample?
A. 1.3 kJ
B. 7.7 kJ
C. 7.5 kJ
D. 220 J
6. The reaction: S(s) + 3F2 (g) -----> SF6 (g)
is studied in a bomb calorimeter. If 6.40 g of sulfur
is reacted with excess fluorine gas in a calorimeter
whose heat capacity is 32.5 kJ/°C, the temperature
inside the calorimeter rises from 21.3°C to 28.7°C.
Determine the heat produced if one mole of sulfur
would react similarly.
A. 4.8 x 102 kJ
B. 1.2 x 103 kJ
3
D. 2.4 x 103 kJ
C. 1.4 x 10 kJ
7. The ∆H for the reaction:
C(s) + 2H2 (g) -----> CH4 (g) is -74.8 kJ.
Determine the ∆H for the reaction:
3CH4 (g) -----> 6H2 (g) + 3C(s)
B. -74.8 kJ
D. +224.4 kJ
10. The enthalpy change for a reaction is equal to
the heat flow for a reaction system only if
measured at,
A. constant pressure
B. constant temperature
C. constant heat capacity D. constant volume
11. The internal energy change ∆Ε of a system can
be determined if;
A. the temperature is known.
B. the work and heat flow are known.
C. the volume change is known.
D. the specific heat is known.
12.What is the specific heat of ethyl alcohol if 700.0 J
of heat are required to raise the temperature of an
80.0-g sample from 30.0°C to 45.0°C?
a.
131 J/(g °C)
b.
0.292 J/(g °C)
c.
0.583 J/(g °C)
d.
0.194 J/(g °C)
e.
1.72 J/(g°C)
13. How much heat is lost when 35.5 g of iron cools
from 429°C to 18.6°C? (The specific heat of iron is
0.450 J/(g °C).)
a.
4820 J b.
6560 J
c.
8240 J d.
14,600 J
e.
32,400 J
14.What is the quantity of heat evolved when 100.0 g
H2O(l) is formed from the combustion of H2(g)
and O2(g)?
H2(g) + ½ O2(g) -----> H2O(l); ∆H°= -285.8 kJ
a. 285.8 kJ b. 2.858 x 104 kJ
c. 51.44 kJ d. 2297 kJ
e. 1586 kJ
15.This question is concerned with the heat change
when ammonia is formed from its elements:
N2(g) + 3H2(g) ----> 2NH3(g); ∆H° = -92 kJ
Therefore, 92 kJ is the quantity of heat which is
a. lost to the surroundings when 1 mol of hydrogen is
consumed.
b. lost to the surroundings when 1 mol of ammonia is
formed.
16
c. lost to the surroundings when 2 mol of ammonia are
formed.
d. gained from the surroundings when 1 mol of
ammonia is formed.
e. gained from the surroundings when 2 mol of
ammonia are formed.
16. Which one of the following would not need to be
included in an Enthalpies of Formation Table
because its ∆H°f is equal to zero ?
a.
Br2(l)
b.
Br2(g)
c.
Br2(s)
d.
Na(l)
e. I2(g)
17. Given the following data,
∆H°(kJ/mol)
-395
S(s) + O2(g) ------> SO2(g)
SO2(g)
------> S(g) + O2(g)
618
Find the heat required for the reaction converting solid
sulfur to gaseous sulfur,
S(s) ----> S(g); ∆H° = ? at 25°C and 1 atm pressure.
a.
+223 kJ/mol b. +618 kJ/mol
c.
-618 kJ/mol d. -223 kJ/mol
e.
-1013 kJ/mol
18. For the reaction
2C2H2(g) + 5O2(g) -----> 4CO2(g) + 2H2O(l); ∆H° = ?
[∆H°f in kJ/mol are O2(g)= 0; C2H2(g)= 226.7;
CO2(g)= -393.5; H2O(l)= -285.8] the ∆H° of reaction is
a.
2(-285.8) + 4(-393.5) + 2(226.7).
b.
2(-285.8) + 4(-393.5) - 2(226.7).
c.
2(285.8) + 4(393.5) + 2(226.7).
d.
2(285.8) + 4(393.5) - 2(226.7).
e.
-285.8 - 393.5 + 226.7.
19. The following two reactions are known.
Fe2O3(s) + 3CO(g) ---->2Fe(s) + 3CO2(g);∆H° = -26.8 kJ
FeO(s) + CO(g) -----> Fe(s) + CO2(g); ∆H° = -16.5 kJ
Determine the ∆H° value for the reaction below.
Fe2O3 (s) + CO(g) ----> 2FeO(s) + CO2(g); ∆H° =?
a.
-43.3 kJ b. -10.3 kJ
c.
6.2 kJ
d. 10.3 kJ
e.
22.7 kJ
20. Thermal energy gained or lost when a heat change
takes place under constant pressure is called the
a. specific heat.
b. ∆H, enthalpy change.
c. heat capacity.
d. thermochemical equation.
21. Calculate the enthalpy change, ∆H°, for the
cumbustion of C3H6(g):
C3H6(g) + 9/2O2(g) -----> 3CO2(g) + 3H2O(l)
H°f values in kJ/mol are as follows: C3H6(g)
= 21; O2(g)= 0; CO2(g) = -394; H2O(l) = -286.
a.
-2061 kJ b. -2019 kJ
c.
-701 kJ
d. 2019 kJ
e.
2061 kJ
22. Which of the following has a standard enthalpy of
formation(∆H°f) value of zero at 25°C and 1.0 atm?
a.
H2O(l)
b. C6H12O6(s)
d. FeSO4(aq)
c.
FeSO4(s)
e. O2(g)
23. Which of the following statements is false?
a.
The reaction vessel cools when an
endothermic reaction occurs.
b.
An exothermic reaction is characterized by a
negative value of ∆H.
c.
Heat is evolved when an exothermic reaction
occurs.
d.
Heat is added to the system by an
endothermic reaction.
e.
An endothermic reaction causes the
surroundings to absorb heat.
24. Which statement about energy is false?
a.
b.
c.
d.
e.
25.
All chemical reactions involve energy.
The study of heat transfer is called thermokinetics.
Energy is the capacity to do work.
Kinetic energy is the energy of motion.
Potential energy is the energy of position.
Which of the following is an example of
potential energy?
a. energy of periodic motion
b. electricity
c. gravitational energy
d. mechanical energy
e. thermal energy
26. Which of the following is an example of
potential energy?
a. hitting a baseball
b. running around bases
c. pitching a baseball
d. a bat lying on the ground
e. sliding into home plate
27. Which of the following is not an example of
kinetic energy?
a. the motion of a molecule
b. the motion of a golf ball
c. the vibration of an object
d. a loosely held brick on the top of a building
e. the motion of electrons through a wire
28. Determine if each of the four situations below
describes kinetic or potential energy.
I
a moving bullet
II
a picture hanging on a wall
III
the bonds in a mixture of H2 and O2
IV
the movement of molecules
I
17
II
IIII
IV
Option 1:
Option 2:
Option 3:
Option 4:
Option 5:
kinetic
kinetic
potential
potential
kinetic
kinetic
potential
kinetic
potential
potential
potential
potential
kinetic
kinetic
kinetic
b.
c.
d.
e.
potential
kinetic
potential
kinetic
potential
a. Option 1
b. Option 2
c. Option 3
d. Option 4
e. Option 5
29. How many joules are there in 150 Calories of
popcorn?
a. 3.6 × 104 J
b. 36 J
c. 6.3 × 105 J
d. 630 J
e. 3.6 × 10-2 J
30. How many kilojoules are there in one glass of milk
containing 110 Calories?
a. 4.6 × 105 kJ
b. 460 kJ
c. 2.6 × 104 kJ
d. 26 kJ
e. 0.46 kJ
31. Determine the incorrect relationship given below.
a. 80.0 cal/g = 312 J/g
b. 1000 cal = 1 kcal
c. 44.0 kJ = 1.05 × 104 cal
d. 1 µJ = 1 × 10-6 J
e. 1000 J = 1 kJ
32. The First Law of Thermodynamics states that:
a. Molecules move faster as temperature increases.
b. The total energy of the universe is constant.
c. Energy transfers from hotter objects to cooler objects.
d. Samples with different temperatures that come in
contact with one another will reach thermal equilibrium.
e. All of the above.
33. For most chemical reactions, the only energy is
transferred through:
a.
heat
b.
heat and light
c.
work
d.
heat and work
e.
heat, light and work
34. Select the process that does not represent the
proper flow of energy from the first named
substance to the second named substance.
a.
Water at 20°C to a thermometer at 25°C
Steel at 100°C to water at 25°C
Water at 25°C to ice at 273 K
A flame to a glass rod initially at room temperature
Dry ice at –78°C to liquid nitrogen at –196°C
35. Which property can be used to distinguish one
substance from another substance?
a. temperature
b. enthalpy
c. internal energy
d. specific heat capacity
e. kinetic energy
36. If a 10.0 g sample of each substance below has 250
J applied to it, which substance will have the
greatest increase in temperature?
a
iron (specific heat = 0.46 J/g)
b.
water (specific heat = 4.184 J/g)
c.
copper (specific heat = 0.39 J/g)
d.
aluminum (specific heat = 0.92 J/g)
e.
lead (specific heat = 0.13 J/g)
37. How much energy is required to raise the
temperature of 100.0 g of water by 25.0°C?
a.
2.05 kJ
b.
4.18 kJ
c.
10.5 kJ
d.
105 kJ
e.
598 kJ
38. How much heat is required to raise the
temperature of 25.0 g of copper (specific heat =
0.39 J/g°C) from 22.0°C to 48.5°C?
a.
0.413 J
b.
158 J
c.
258 J
d.
1670 J
e.
2770 J
39. A 10.0 g sample of iron (specific heat = 0.46 J/g°C)
has an initial temperature of 20.0°C. If 265 J of
heat are applied to the iron, what is its final
temperature?
a.
12.1°C
b.
26.3°C
c.
32.1°C
d.
57.6°C
e.
77.6°C
40. The temperature of a 15.5 g sample of a metal
rises 35.0°C when 125 J of energy is applied to it.
What is the identity of the metal?
a. silver (specific heat = 0.23 J/g°C)
b. copper (specific heat = 0.39 J/g°C)
c. iron (specific heat = 0.46 J/g°C)
d. lead (specific heat = 0.13 J/g°C)
e. aluminum (specific heat = 0.92 J/g°C)
18
41. What is the molar heat capacity of lead
(specific heat = 0. 13 J/g°C)?
a. 10.7 J mol-1 °C-1
b. 26.9 J mol-1 °C-1
c. 343 J mol-1 °C-1
d. 866 J mol-1 °C-1
e. 7.83 × 1022 J mol-1 °C-1
42. What is the molar heat capacity of table salt, NaCl
(specific heat = 0.88 J/g°C)?
a. 117 J mol-1 °C-1
b. 24.6 J mol-1 °C-1
c. 245 J mol-1 °C-1
d. 51.4 J mol-1 °C-1
e. 5.30 × 1022 J mol-1 °C-1
43. Which substance has the highest molar heat
capacity?
a. aluminum (specific heat = 0.92 J/g°C)
b. copper (specific heat = 0.39 J/g°C)
c. iron (specific heat = 0.46 J/g°C)
d. silver (specific heat = 0.23 J/g°C)
e. lead (specific heat = 0.13 J/g°C)
44. Determine the amount of heat required to raise
the temperature of a 153 g bar of gold by 50.0°C.
(specific heat of gold = 0.128 J/g°C)
a. 5.98 × 104 J
b. 490 J
c. 979 J
d. 1.47 × 103 J
e. 7.65 × 103 J
45 Determine the quantity of ice required to absorb
exactly 50 kJ of energy when the ice warms from 50.0°C to -10.0°C (specific heat of ice = 2.06
J/g°C).
a. 485 g
b. 607 g
c. 0.607 g
d. 2.43 × 103 g
e. 0.485 g
46. A sample of water containing 2.00 moles is initially
at 30.0°C. If the sample absorbs 2.00 kJ of heat,
what is the final temperature of the water?
(specific heat of water = 4.184 J/g°C)
a. 30.2°C
b. 269°C
c. 13.3°C
d. 43.3°C
e. 46.7°C
47. How much heat is required to melt 125 g of ice at
0°C?
a. 0.375 J
b. 333 J
48.
49.
50.
51
52.
53.
54.
19
c. 523 J
d. 41.6 kJ
e. 283 kJ
How much energy is required to melt 10.0 g of ice
at 0.0°C, warm it to 100.0°C and completely
vaporize the sample?
a. 343 J
b. 3330 J
c. 4180 J
d. 22600 J
e. 30100 J
Which process is exothermic?
a. boiling water
b. evaporating alcohol
c. condensing steam
d. warming milk
e. subliming dry ice
Which term refers to a quantity of heat
transferred at constant pressure?
a. entropy
b. enthalpy
c. work
d. specific heat capacity
e. expansion
Which statement is true?
a. A positive change in enthalpy occurs with endothermic processes.
b. A positive change in enthalpy occurs with exothermic processes.
c. A positive change in enthalpy occurs when work is done on the surr
d. A positive change in enthalpy occurs when work is done on the syst
e. A positive change in enthalpy occurs when a process is endothermic
surroundings.
Which statement about the reaction below is
incorrect? H2O(l) → H2O(g)
∆H = +44.0 kJ
a. The value for the gas to liquid value has the reverse sign.
b. The value for the solid to liquid transformation is the same.
c. The value for evaporating 2 moles of water is 88.0 kJ.
d. The reaction is endothermic.
e. The above data does not give any information about the solid to
liquid transformation.
How much energy is produced when 22.5 g of CH4
are burned in sufficient O2?
CH4(g) + 2O2(g) → CO2(g) + 2H2O(l) ∆H = -890 kJ
a. -890 kJ
b. +890 kJ
c. -39.5 kJ
d. -1250 kJ
e. +1250 kJ
How much energy is produced when 225 g of C2H2
are burned in sufficient O2?
∆H =
C2H2(g) + 5/2O2(g) → 2CO2(g) + H2O(l)
-1300 kJ
a. +1.1 × 104 kJ
b. -1.1 × 104 kJ
c. +2.93 × 105 kJ
d. -2.93 × 105 kJ
c.
e. -3.39 × 104 kJ
31.6°C
d.
55. What is the enthalpy change for the combustion of
43.5°C
4.73 g C4H10 in sufficient oxygen?
e.
4.35 × 10-3°C
C4H10(g) + 13/2O2(g) → 4CO2(g) + 5H2O(g)
61. A bomb calorimeter has a heat capacity of 843
∆H = -1895 kJ
J/°C and contains 473 g of water. If the
a. -32.7 kJ
combustion of 0.500 mole of a hydrocarbon
b. -401 kJ
increases the temperature of the calorimeter
c. -23200 kJ
from 22.73°C to 26.95°C, determine the heat
d. -8960 kJ
evolved per mole of hydrocarbon.
e. -155 kJ
a.
8380 kJ
56. The combustion of 1.47 g of methanol produces
b.
23.8 kJ
29.3 kJ of heat. Determine the ∆H for the reaction
c.
76.0 kJ
and its sign.
d.
8.38 kJ
CH3OH(l) + 3/2O2(g) → CO2(g) + 2H2O(g)
e.
95.9 kJ
a. -638 kJ
62. Based on the equation below, which statement is
b. +938 kJ
incorrect?
c. +638 kJ
∆H° = - 571.7 kJ
2H2(g) + O2(g) → 2H2O(l)
d. -938 kJ
a.
If the equation above is divided by 2, ∆H° = - 285.8 kJ.
e. -1.35 kJ
b.
If the equation above is reversed, ∆H° = + 571.1 kJ.
57. When does an exothermic reaction occur?
c.
The value of 571.1 kJ applies to one mole of liquid water.
a. when bonds are broken
d.
Per half mole of O2, ∆H° -285.8 kJ.
b. when bonds are formed
e.
If the state of water changes from the liquid state to the gas state
c. when the energy of bonds breaking is greater than the energy of bonds
formed
applies.
d. when the energy of bonds breaking is less than the energy
bonds formed
63. of
Determine
the heat of reaction for the process
e. when stronger bonds are broken and weaker bonds are formed
Fe2O3(s) + FeO(s) → Fe3O4(s)
58. The temperature of 3.50 kg of water is raised by
using the information given below:
1.17°C when 1.00 g of hydrazine N2H4 is burned in
a bomb calorimeter. The calorimeter has a heat
2Fe(s) + O2(g) → 2FeO(s)
∆H° = -544.0 kJ
capacity of 1883 J/°C. How much heat is given off
4Fe(s) + 3O2(g) → 2Fe2O3(s)
∆H° = -1648.8 kJ
by the sample?
3Fe(s) + 2O2(g) → Fe3O4(s)
∆H° = -1118.4 kJ
a. 14.6 kJ
b. 17.1 kJ
a.
-1074.0 kJ
c. 19.3 kJ
b.
22.2 kJ
d. 22.5 kJ
c.
1074.0 kJ
e. 94.2 kJ
d.
-22.0 kJ
59. A bomb calorimeter has a heat capacity of 783
e.
249.8 kJ
J/°C and contains 254 g of water. How much
64. Determine the heat of reaction for the process
energy is evolved or absorbed when the
C2H4(g) + 6HCl(g) → 2CHCl3(g) + 4H2(g)
temperature of the calorimeter goes from
using the information given below:
23.73°C to 26.01°C?
∆H° = 52.3 kJ
2C(s) + 2H2(g) → C2H4(g)
a.
4210 kJ evolved
H2(g) + Cl2(g) → 2HCl(g)
∆H° = -184.6kJ
b.
2420 kJ absorbed
C(s) + 1/2H2(g) + 3/2Cl2(g) →
∆H° = -103.1 kJ
c.
4.21 kJ evolved
CHCl3(g)
d.
2.42 kJ evolved
e.
1.78 kJ evolved
a. + 398.4 kJ
60. A 0.100 mole sample of CH4 reacts in a
b. + 295.3 kJ
calorimeter having a heat capacity of 783 J/°C.
c. -29.2 kJ
The calorimeter contains 254 g of water.
d. -295.3 kJ
Determine the temperature increase of the
e. +29.2 kJ
calorimeter.
65. Determine the heat of reaction for the process
∆H = CH4(g) + 2O2(g) → 2H2O(g) + CO2(g)
TiO2(s) + 4HCl(g) → TiCl4(l) + 2H2(g) + O2(g)
802.3 kJ
using the information given below:
a.
7.56°C
∆H° = -939.7 kJ
Ti(s) + O2(g) → TiO2(s)
b.
10.2°C
2HCl(g) → H2(g) + Cl2(g)
∆H° = -184.6 kJ
20
Ti(s) + 2Cl2(g) → TiCl4(l)
∆H° = -804.2 kJ
a.
-149.6 kJ
b.
328.8 kJ
c.
-328.8 kJ
a. -320.1 kJ
d.
812.6 kJ
b. 233.7 kJ
e.
213.4 kJ
c. 320.1 kJ
70. The standard enthalpies of formation for several
d. -233.7 kJ
substances are given below:
e. 504.7 kJ
FeCl2(s) = -341.8 kJ/mol
FeS2(s) = -178.2 kJ/mol
66. The standard enthalpies of formation for several
HCl(g) = -92.3 kJ/mol
FeCl3(s) = -399.5 kJ/mol
substances are given below:
H2S(g) = -20.6 kJ/mol
HCl(aq) = -167.1 kJ/mol
-110.5 kJ/mol
CO2(g)
-393.5 kJ/mol
CO(g)
H2O(g) = -271.8 kJ/mol
-285.8 kJ/mol
H2O(g)
-241.8 kJ/mol
H2O(l)
Calculate the ∆H° for the reaction below.
-187.8 kJ/mol
CH3OH(g)
-200.7 kJ/mol
H2O2(l)
C2H5OH(l) -277.7 kJ/mol
C2H5OH(g) -235.1 kJ/mol
2FeCl2(s) + 2HCl(g) → 2FeCl3(s) + H2(g)
a.
69.2 kJ
Determine the ∆H° for the reaction below.
b.
219.0 kJ
2CO(g) + 4H2(g) → C2H5OH(g) + H2O(g)
c.
34.6 kJ
a. 255.9 kJ
d.
-69.2 kJ
b. -299.9 kJ
e.
-219.0 kJ
c. -255.9 kJ
71. Why is hydrogen gas impractical to use as fuel for
d. -366.4 kJ
most energy needs?
e. -298.5 kJ
a.
Hydrogen has a low fuel value.
67. The standard enthalpies of formation for several
b.
Hydrogen does not combust.
substances are given below:
Hydrogen is not readily available.
-110.5 kJ/mol
CO2(g)
-393.5 kJ/mol c.
CO(g)
Hydrogen produces carbon dioxide when burned.
H2O(l)
-285.8 kJ/mol
H2O(g)
-241.8 kJ/mol d.
Hydrogen cannot be stored under pressure.
-187.8 kJ/mol
CH3OH(g)
-200.7 kJ/mol e.
H2O2(l)
72. Which of the following is a biomass fuel?
C2H5OH(l)
-277.7 kJ/mol
C2H5OH(g)
-235.1 kJ/mol
a.
coal
Determine the ∆H° for the reaction below.
b.
hydrogen
C2H5OH(l) + 3O2(g) → 2CO2(g) + 3H2O(1) + O2(g)
c.
oil
a. -1234.7 kJ
d.
wood
b. -1366.7 kJ
e.
natural
gas
c. -1324.1 kJ
73.
Which
of
the
following
properties is desirable in a
d. -401.8 kJ
chemical fuel?
e. +1234.7 kJ
a. They should react exothermically with oxygen.
68. The standard enthalpies of formation for several
b. They should be available at a reasonable cost.
substances are given below:
CO(g)
-110.5 kJ/mol
CO2(g)
-393.5 kJ/mol c. They should produce little environmental damage.
H2O(l)
-285.8 kJ/mol
H2O(g)
-241.8 kJ/mol d. They should be available in reasonable quantities.
-187.8 kJ/mol
CH3OH(g)
-200.7 kJ/mol e. All of the above are desirable properties.
H2O2(l)
74. What is the average caloric value of a
C2H5OH(l)
-277.7 kJ/mol
C2H5OH(g)
-235.1 kJ/mol
carbohydrate?
Determine the heat of vaporization for liquid H2O
a. 1 Cal/g
and C2H5OH.
b. 4 Cal/g
a. 241.8 and -235.1 kJ
c. 7 Cal/g
b. -54.0 and -42.6 kJ
d. 9 Cal/g
c. -44.0 and -42.6 kJ
e. 12 Cal/g
d. 44.0 and 42.6 kJ
75. What is the average caloric value of fat?
e. 241.8 and 325.1 kJ
a. 1 Cal/g
69. The standard enthalpies of formation for several
b. 4 Cal/g
substances are given below:
c. 7 Cal/g
FeCl2(s) = -341.8 kJ/mol
FeS2(s) = -178.2 kJ/mol
d. 9 Cal/g
HCl(g) = -92.3 kJ/mol
FeCl3(s) = -399.5 kJ/mol
e. 12 Cal/g
HCl(aq) = -167.1 kJ/mol
H2S(g) = -20.6 kJ/mol
76.
Which statement about foods as a source of energy
H2O(g) = -271.8 kJ/mol
is false?
Calculate the ∆Hº for the reaction below.
a. Protein and carbohydrates have approximately the same caloric valu
2FeS2(s) + 8HCl(g) → 2FeCl3(s) + 4H2S(g) +
b. Carbohydrates are the body's primary source of energy.
Cl2(g)
21
c.
d.
e.
Metabolism releases energy from carbohydrates and proteins
not fats.
46.but
ANS:
D
Fat is stored energy.
47. ANS: D
The caloric value of food can be determined using a bomb 48.
calorimeter.
ANS: E
49. ANS: C
Answers to questions:
50. ANS: B
1. C. exothermic
51. ANS: A
2. D. Both iron and copper samples will be at the
52. ANS: B
same final temperature.
53. ANS: D
3. D. -173 J
54. ANS: B
4. C. 31°C
55. ANS: E
5. A. 1.3 kJ
56. ANS: A
57. ANS: D
6. B. 1.2 x 103 kJ
58. ANS: C
7. D. .+224.4 kJ
59. ANS: C
8. D. 7.40
60. ANS: D
9. C. O2(g)
61. ANS: E
10. A. constant pressure
62. ANS: C
11. B. the work and heat flow are known.
63. ANS: D
12.
>
c 0.583 J/(g °C)
64. ANS: B
13.
>
b 6560 J
65. ANS: D
14.
>
e 1586 kJ
66. ANS: C
15.
>
c lost to the surroundings when 2
67. ANS: B
mol of ammonia are formed.
68. ANS: D
16.
>
a Br2(l)
69. ANS: E
70. ANS: A
17.
>
a +223 kJ/mol
71. ANS: C
18.
>
b 2(-285.8) + 4(-393.5) - 2(226.7).
72. ANS: D
19.
>
c 6.2 kJ
73. ANS: E
20.
>
b ∆H, enthalpy change.
74. ANS: B
21.
>
a -2061 kJ
75. ANS: D
22.
>
e O2(g)
76. ANS: C
23.
>
e An endothermic reaction causes
the surroundings to absorb heat.
24. b. The study of heat transfer is called
thermokinetics.
25. c.gravitational energy
26. d .a bat lying on the ground
27. d. a loosely held brick on the top of a building
28. b. Option 2
29. c. 6.3 × 105 J
30. b. 460 kJ
31. a. 80.0 cal/g = 312 J/g
32. b. The total energy of the universe is constant.
33. d. heat and work
34. a. Water at 20°C to a thermometer at 25°C
35. d. specific heat capacity
36. e. lead (specific heat = 0.13 J/g)
37. c. 10.5 kJ
38. ANS: C
39.
ANS:
E
40. ANS: A
REF: Section 6.3
41. ANS: B
REF: Section 6.3
42. ANS: D
REF: Section 6.3
43. ANS: E
REF: Section 6.3
44. ANS: C
REF: Section 6.3
45. ANS: B
REF: Section 6.3
22
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Section 6.3
Section 6.4
Section 6.4
Section 6.4
Section 6.4
Section 6.4
Section 6.5
Section 6.6
Section 6.6
Section 6.6
Section 6.6
Section 6.7
Section 6.8
Section 6.8
Section 6.8
Section 6.8
Section 6.9
Section 6.9
Section 6.9
Section 6.9
Section 6.10
Section 6.10
Section 6.10
Section 6.10
Section 6.10
Section 6.11
Section 6.11
Section 6.11
Section 6.12
Section 6.12
Section 6.12