CHEM 116 ACTUAL EXAM QUESTIONS WITH ANSWERS
2025/2026
Which one of the following correctly indicates the relationshop between the entropy of a
system and the number of different arrangement, W, in the system? - S = k lnW
The entropy change accompanying any process is given by the equation - DeltaS = k
ln(Wfinal/Winitial)
Of the following, the entropy of gaseous ___ is the largest at 25 C and 1 atm... - C2H6
Of the following, the entropy of ___ is the largest. - HI(g)
For an isothermal process, the entropy change of the surroundings is given by the
equation - DeltaS = -qsys/T
The standard Gibbs free energy of formation of ___ is zero. a) H2O(l) b) O(g) c)H2(g) -
C only - H2(g)
The standard Gibbs free energy of formation of ___ is zero. a) H2O(l) b) Na(s) c)H2(g) -
B and C - b) Na(s) c)H2(g)
The standard Gibbs free energy of formation of ___ is zero. a) Al(s) b) Br2(l) c) Hg(l) -
All - a) Al(s) b) Br2(l) c) Hg(l)
DeltaH is +137 kJ/mol and DeltaS is +120 J/Kmol. This reaction is ___. - spontaneous
only at high temperature
A reaction that is NOT spontaneous at low temperature can become spontaneous at
hight temperature if DeltaH is___ and DeltaS is ____. - Positive, Positive
For a reaction to be spontaneous under standard conditions at all temperatures, the
signs of DeltaH and DeltaS must be ___ and ___, respectively. - Negative, Positive
With thermodynamics, one cannot determine ____. - the speed of a reaction.
If DeltaG for a reaction is greater than zero, then ____. - K < 1
If DeltaG for a reacton s less than zero, then - K > 1
T/F The melting of a substance at its melting point is an isothermal process. - True
The vaporization of a substance at its boiling point is an isothermal process. - True
The quantity of energy gained by a system equals the quantity of energy gained by its
surroundings. - False
, The entropy of a pure crystalline substance at 0 C is zero. - False
The more negative DeltaG is for a given reaction, the larger the value of the
corresponding equilibrium constant, K. - True
The gain of electrons by an element I called - Reduction
____ is reduced in Cr2O7+6S2O3+14H -> 2Cr +3S4O6+7H2O - Cr 6+
____ is the oxisizing agent in Cr2O7+6S2O3+14H -> 2Cr +3S4O6+7H2O - Cr2O7 2-
Which substance is serving as the reducing agent in the following 14H+Cr2O7+3Ni ->
3Ni+2Cr+7H2O - Ni
Which substance is the reducing agent in the reaction Pb+PbO2+2H2So4 ->
2PbSO4+2H2O - Pb
What is the oxidation number of chromium in Cr2O7 ion? - +6
What is the oxidation number of potassium in KMnO4? - +1
What is the oxidation number of manganese in the MnO4 1- ion? - +7
What is the oxidation number of manganese in MnO2? - +4
___ electrons appear in the following half-reaction when it is balanced S4O6 -> 2SO3 -
2
The balanced half-reaction in which chlorine gas s reduced to the aqueous chloride ion
is a ____ process. - six-electron
The balanced half-reaction in which dichromate ion is reduced to chromium metal is a
____ process. - twelve-electron
The balanced half-reaction in which dichromate ion is reduced to chromium (III) ion is a
+____ process. - six-electron
The balanced half-reaction in which sulfate ion is reduced to sulfite ion is a ___ process.
- two-electron
The electrode at which oxidation occurs is called the - anode
The half-reaction occurng at the anode in the alanced reaction shown below is ___.
3MnO4+24H+5Fe -> 3Mn+5Fe+12H2O - Fe(s)->Fe 3+(aq) + 3e-
2025/2026
Which one of the following correctly indicates the relationshop between the entropy of a
system and the number of different arrangement, W, in the system? - S = k lnW
The entropy change accompanying any process is given by the equation - DeltaS = k
ln(Wfinal/Winitial)
Of the following, the entropy of gaseous ___ is the largest at 25 C and 1 atm... - C2H6
Of the following, the entropy of ___ is the largest. - HI(g)
For an isothermal process, the entropy change of the surroundings is given by the
equation - DeltaS = -qsys/T
The standard Gibbs free energy of formation of ___ is zero. a) H2O(l) b) O(g) c)H2(g) -
C only - H2(g)
The standard Gibbs free energy of formation of ___ is zero. a) H2O(l) b) Na(s) c)H2(g) -
B and C - b) Na(s) c)H2(g)
The standard Gibbs free energy of formation of ___ is zero. a) Al(s) b) Br2(l) c) Hg(l) -
All - a) Al(s) b) Br2(l) c) Hg(l)
DeltaH is +137 kJ/mol and DeltaS is +120 J/Kmol. This reaction is ___. - spontaneous
only at high temperature
A reaction that is NOT spontaneous at low temperature can become spontaneous at
hight temperature if DeltaH is___ and DeltaS is ____. - Positive, Positive
For a reaction to be spontaneous under standard conditions at all temperatures, the
signs of DeltaH and DeltaS must be ___ and ___, respectively. - Negative, Positive
With thermodynamics, one cannot determine ____. - the speed of a reaction.
If DeltaG for a reaction is greater than zero, then ____. - K < 1
If DeltaG for a reacton s less than zero, then - K > 1
T/F The melting of a substance at its melting point is an isothermal process. - True
The vaporization of a substance at its boiling point is an isothermal process. - True
The quantity of energy gained by a system equals the quantity of energy gained by its
surroundings. - False
, The entropy of a pure crystalline substance at 0 C is zero. - False
The more negative DeltaG is for a given reaction, the larger the value of the
corresponding equilibrium constant, K. - True
The gain of electrons by an element I called - Reduction
____ is reduced in Cr2O7+6S2O3+14H -> 2Cr +3S4O6+7H2O - Cr 6+
____ is the oxisizing agent in Cr2O7+6S2O3+14H -> 2Cr +3S4O6+7H2O - Cr2O7 2-
Which substance is serving as the reducing agent in the following 14H+Cr2O7+3Ni ->
3Ni+2Cr+7H2O - Ni
Which substance is the reducing agent in the reaction Pb+PbO2+2H2So4 ->
2PbSO4+2H2O - Pb
What is the oxidation number of chromium in Cr2O7 ion? - +6
What is the oxidation number of potassium in KMnO4? - +1
What is the oxidation number of manganese in the MnO4 1- ion? - +7
What is the oxidation number of manganese in MnO2? - +4
___ electrons appear in the following half-reaction when it is balanced S4O6 -> 2SO3 -
2
The balanced half-reaction in which chlorine gas s reduced to the aqueous chloride ion
is a ____ process. - six-electron
The balanced half-reaction in which dichromate ion is reduced to chromium metal is a
____ process. - twelve-electron
The balanced half-reaction in which dichromate ion is reduced to chromium (III) ion is a
+____ process. - six-electron
The balanced half-reaction in which sulfate ion is reduced to sulfite ion is a ___ process.
- two-electron
The electrode at which oxidation occurs is called the - anode
The half-reaction occurng at the anode in the alanced reaction shown below is ___.
3MnO4+24H+5Fe -> 3Mn+5Fe+12H2O - Fe(s)->Fe 3+(aq) + 3e-
