Name: 
 

Chemistry 12 - Chapter 5 Quiz



True/False
Indicate whether the sentence or statement is true or false.
 

1. 

Nuclear changes generally absorb more energy than chemical changes.
 

2. 

In exothermic reactions, the reactants have more kinetic energy than the products.
 

3. 

On a potential energy diagram, the horizontal axis may be called reaction progress.
 

4. 

In endothermic reactions, the heat term is written on the right side of the equation.
 

5. 

In an isolated system, neither matter nor energy may enter or leave the system.
 

6. 

In calorimetry, the assumption is made that the enthalpy change of the system equals the heat transferred to the surroundings.
 

7. 

The burning of gasoline is an example of an endothermic physical change.
 

8. 

A formation reaction has elements in their standard states as reactants.
 

9. 

Specific heat capacity is the amount of heat required to change a given mass through 1°C.
 

10. 

The c12-ch5_files/i0110000.jpgH value for an exothermic reaction is negative.
 

Multiple Choice
Identify the letter of the choice that best completes the statement or answers the question.
 

11. 

Which of the following would involve the largest production of heat per mole?
a.
the burning of gasoline
b.
the evaporation of water
c.
the fission of uranium
d.
the freezing of water
e.
the rusting of iron
 

12. 

Which of the following would involve the greatest absorption of heat per mole?
a.
the burning of gasoline
b.
the evaporation of water
c.
the fission of uranium
d.
the freezing of water
e.
the rusting of iron
 

13. 

The evaporation of methanol (molar mass 32.0 g/mol) involves absorption of 1.18 kJ/g. What is the molar enthalpy of vaporization of methanol?
a.
0.0369 kJ/mol
b.
1.18 kJ/mol
c.
3.78 kJ/mol
d.
32.0 kJ/mol
e.
37.8 kJ/mol
 

14. 

When solid ammonium chloride is added to water, the solution feels cold to the hand. Which statement best describes the observation?
a.
NH4Cl(s) c12-ch5_files/i0160000.jpg NH4Cl(aq) + 34 kJ
b.
The reaction is exothermic.
c.
NH4Cl(s) c12-ch5_files/i0160001.jpg NH4Cl(aq)      c12-ch5_files/i0160002.jpgH = 34 kJ
d.
The system releases heat, so it feels colder.
e.
The boiling point is increased, so it feels colder.
 

15. 

Which of the following statements is not true?
a.
c12-ch5_files/i0170000.jpgH is the difference in enthalpy between reactants and products.
b.
c12-ch5_files/i0170001.jpgH may be written as part of the equation.
c.
c12-ch5_files/i0170002.jpgH is negative for an endothermic reaction.
d.
A reaction consumes heat if c12-ch5_files/i0170003.jpgH is positive.
e.
c12-ch5_files/i0170004.jpgH equals the heat transferred to or from the surroundings.
 

16. 

Referring to the reaction below, how much heat is released if 120 g of potassium metal reacts?
2 K(s)  +  2 H2O(l)  c12-ch5_files/i0180000.jpg  160 kJ  +  H2(g)  +  2 KOH(aq)
a.
0.0 kJ since no temperature change is indicated
b.
52.1 kJ
c.
246 kJ
d.
491 kJ
e.
280 KJ
 

17. 

The standard heat of formation of solid ammonium nitrate, NH4NO3, is -330 kJ/mol . The equation that represents this process is:
a.
N2(g)  +  4 H2(g)  +  3 O2(g)  c12-ch5_files/i0190000.jpg  NH4NO3(s)  +  330 kJ
b.
2 N(g)  +  4 H(g)    3 O(g)  c12-ch5_files/i0190001.jpg  NH4NO3(s)   +   330 kJ
c.
NH4+(g)  +  NO3-(g)  c12-ch5_files/i0190002.jpg  NH4NO3(s)  +  330 kJ
d.
c12-ch5_files/i0190003.jpgN2(g)  +  2 H2(g)  +  c12-ch5_files/i0190004.jpgO2(g)  c12-ch5_files/i0190005.jpg  NH4NO3(s)  +  330 kJ
e.
N2(g)  +  2 H2(g)  +  c12-ch5_files/i0190006.jpgO2(g)  c12-ch5_files/i0190007.jpg  NH4NO3(s)  +  330 KJ
 

18. 

Consider the following two thermochemical equations:
N2(g)  +  c12-ch5_files/i0200000.jpgO2(g)  c12-ch5_files/i0200001.jpg  N2O5(s)      c12-ch5_files/i0200002.jpgH = x kJ
N2(g)c12-ch5_files/i0200003.jpgO2(g)  c12-ch5_files/i0200004.jpg  N2O5(g)      c12-ch5_files/i0200005.jpgH = y  kJ
      The enthalpy change, in kJ, for the sublimation of one mole of N2O5 solid to gas would be represented by the quantity
a.
x + y
b.
x - y
c.
y - x
d.
-x - y
e.
xy
 



 
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