ACS CHEMISTRY GENERAL EXAM 2024 ACTUAL
EXAM 2 VERSIONS (VERSION A AND B)
COMPLETE 400 QUESTIONS WITH DETAILED
VERIFIED ANSWERS /ALREADY GRADED A
The higher the activation energy: - ANSWER the slower the reaction.
Which one of the following substances in their liquid phase experiences only
dispersion forces? - ANSWER CH4
Ammonia has a normal boiling point of -33.3°C, and a heat of vaporization of 23.4
kJ/mol.
What is the phase of ammonia at -40.0 ºC at 1.00 atm? - ANSWER liquid
The activation energy of a reaction depends on:
a. Both of the answers are correct.
b. concentration
c. temperature
d. Neither answer is correct. - ANSWER d. neither answer is correct
Activation energy depends on the nature of the chemical transformation that takes
place, but not on the relative energy state of the reactants and products.
Sublimation occurs at 1 atm and 25.0º C: - ANSWER when the triple point is above 1
atm pressure.
The change in the concentration of a reactant: - ANSWER is always a negative
number.
The reaction, 2X + 2Y→ Z, was found to obey the rate law: Rate = k[X]2[Y]2. Two
experiments were done. In the 2nd experiment, the concentrations of both X and Y
were doubled compared to the 1st How much faster was the initial rate in the 2nd
experiment compared to the 1st experiment? - ANSWER 16 times faster
The activation energy (Ea) of a reaction can be determined from the graph of ln(k)
vs. 1/T where k is the rate constant of a reaction, T is the temperature, and R is the
gas constant. Such a plot yields a straight line with slope equal to: - ANSWER -Ea/R
The heat of vaporization of a substance depends on:
intermolecular forces
All of the answers are correct.
the molecular shape of the substance.
the molar mass of the substance - ANSWER All of the answers are correct.
What is the main reason that reaction rate increases with temperature? - ANSWER
The fraction of molecules with enough energy to react increases with temperature.
,The slowest step in a certain reaction mechanism is:
A + B → 2C
What is the order of this elementary step? - ANSWER 2
The overall reaction order of a reaction is 3. Units of the rate of the reaction are: -
ANSWER M/s
In the reaction:
2A + B → 3C
which expression is the rate of the reaction? - ANSWER 1/3( Δ[C]/Δt)
Which compound experiences hydrogen bonding?
a. H2s
b. all the answers are correct
c. HF
d. HCl - ANSWER c. HF
Hydrogen bonding to F, N, or O
When melting a pure substance during a heating curve, the temperature does not
increase even though heat is being added.
Why is this? - ANSWER The energy is being used to break the intermolecular forces.
Which pair of compounds will make a buffer solution?
a. NaOH and HNO3
b. HCl and NaCl
c. KNO2 and HNO2
d. NaF and KF - ANSWER c. KNO2 and HNO2 (weak Acid)
weak acid + conjugate base or weak base + conjugate acid.
seven strong acids: HCl, HBr, HI, HNO3, H2SO4, HClO4, & HClO3
In a titration curve , what quantity does the x-axis represent? - ANSWER the total
volume of base added
The reaction:
A(l) + 2B(g) ⇄ 3C2(g) is allowed to reach equilibrium in a closed bottle. The
pressure is then increased. What happens?
a. Nothing happens.
b. The reaction shifts to the right.
c. The reaction shifts to the left.
d. You need to know whether the reaction is exothermic or endothermic to answer
this question. - ANSWER c. The reaction shifts to the left
In complex ion formation, metal cations bind to what? - ANSWER Ligands
Which is the strongest of these four acids? - ANSWER HNO3
What is the pOH of a 10.0 M NaOH solution? - ANSWER -1.00
In what solution would PbCl2 be more soluble than in pure water?
, a. 0.100 M NaCl
b. 0.100 M Pb(NO3)2
c. None of the answers are correct.
d. 0.10 M NaF - ANSWER c. None of the answers are correct.
Consider the reaction:
NH4HS(s) ⇄ NH3(g) + H2S(g)
An equilibrium mixture of this reaction at a certain temperature has [NH3] = [H2S ] =
0.78 M. What is Kc for this reaction? - ANSWER 0.61
Once equilibrium has been established: - ANSWER the reactant and product
concentrations do not change.
Which ion is basic when dissolved in water?
a. Mg2+
b. CN-
c. NO3-
d. NH4+ - ANSWER b. CN-
What is [H3O+] for a solution of pH = 2.22? - ANSWER 6.0 x 10-3 M
How does the Kb of a weak base change as a solution of it is made more
concentrated? - ANSWER It does not change.
What an insoluble salt is put in water, an equilibrium is established between: -
ANSWER the solid salt and its ions.
Methylamine is a weak base. What can we say about the reaction of this base with
water? - ANSWER ∆G > 0, K <1
Which of the following results in a ∆S,universe which is greater than 0? - ANSWER
the melting of ice at 298.15K
Which of the following metals with dissolve in 1.0 M HCl?
a. Ag
b. Au
c. None of the answers are correct
d. Cu - ANSWER c. None of the answers are correct
In a voltaic cell, what would happen if there was no salt bridge? - ANSWER There
would be no current.
The connection between ∆Gº and Eºcell is given by: ∆Gº = -nFEºcell
Consider the reaction:
Fe2+(aq) + 2Li(s) → Fe(s) + 2Li+(aq)
What is n for this reaction? - ANSWER 2
For a particular reaction at 298.15 K, ∆Hº = 23.2 kJ and ∆Sº is 134 J/K. What can we
say about this reaction? - ANSWER It is nonspontaneous at low temperatures but
becomes spontaneous at higher temperatures.
EXAM 2 VERSIONS (VERSION A AND B)
COMPLETE 400 QUESTIONS WITH DETAILED
VERIFIED ANSWERS /ALREADY GRADED A
The higher the activation energy: - ANSWER the slower the reaction.
Which one of the following substances in their liquid phase experiences only
dispersion forces? - ANSWER CH4
Ammonia has a normal boiling point of -33.3°C, and a heat of vaporization of 23.4
kJ/mol.
What is the phase of ammonia at -40.0 ºC at 1.00 atm? - ANSWER liquid
The activation energy of a reaction depends on:
a. Both of the answers are correct.
b. concentration
c. temperature
d. Neither answer is correct. - ANSWER d. neither answer is correct
Activation energy depends on the nature of the chemical transformation that takes
place, but not on the relative energy state of the reactants and products.
Sublimation occurs at 1 atm and 25.0º C: - ANSWER when the triple point is above 1
atm pressure.
The change in the concentration of a reactant: - ANSWER is always a negative
number.
The reaction, 2X + 2Y→ Z, was found to obey the rate law: Rate = k[X]2[Y]2. Two
experiments were done. In the 2nd experiment, the concentrations of both X and Y
were doubled compared to the 1st How much faster was the initial rate in the 2nd
experiment compared to the 1st experiment? - ANSWER 16 times faster
The activation energy (Ea) of a reaction can be determined from the graph of ln(k)
vs. 1/T where k is the rate constant of a reaction, T is the temperature, and R is the
gas constant. Such a plot yields a straight line with slope equal to: - ANSWER -Ea/R
The heat of vaporization of a substance depends on:
intermolecular forces
All of the answers are correct.
the molecular shape of the substance.
the molar mass of the substance - ANSWER All of the answers are correct.
What is the main reason that reaction rate increases with temperature? - ANSWER
The fraction of molecules with enough energy to react increases with temperature.
,The slowest step in a certain reaction mechanism is:
A + B → 2C
What is the order of this elementary step? - ANSWER 2
The overall reaction order of a reaction is 3. Units of the rate of the reaction are: -
ANSWER M/s
In the reaction:
2A + B → 3C
which expression is the rate of the reaction? - ANSWER 1/3( Δ[C]/Δt)
Which compound experiences hydrogen bonding?
a. H2s
b. all the answers are correct
c. HF
d. HCl - ANSWER c. HF
Hydrogen bonding to F, N, or O
When melting a pure substance during a heating curve, the temperature does not
increase even though heat is being added.
Why is this? - ANSWER The energy is being used to break the intermolecular forces.
Which pair of compounds will make a buffer solution?
a. NaOH and HNO3
b. HCl and NaCl
c. KNO2 and HNO2
d. NaF and KF - ANSWER c. KNO2 and HNO2 (weak Acid)
weak acid + conjugate base or weak base + conjugate acid.
seven strong acids: HCl, HBr, HI, HNO3, H2SO4, HClO4, & HClO3
In a titration curve , what quantity does the x-axis represent? - ANSWER the total
volume of base added
The reaction:
A(l) + 2B(g) ⇄ 3C2(g) is allowed to reach equilibrium in a closed bottle. The
pressure is then increased. What happens?
a. Nothing happens.
b. The reaction shifts to the right.
c. The reaction shifts to the left.
d. You need to know whether the reaction is exothermic or endothermic to answer
this question. - ANSWER c. The reaction shifts to the left
In complex ion formation, metal cations bind to what? - ANSWER Ligands
Which is the strongest of these four acids? - ANSWER HNO3
What is the pOH of a 10.0 M NaOH solution? - ANSWER -1.00
In what solution would PbCl2 be more soluble than in pure water?
, a. 0.100 M NaCl
b. 0.100 M Pb(NO3)2
c. None of the answers are correct.
d. 0.10 M NaF - ANSWER c. None of the answers are correct.
Consider the reaction:
NH4HS(s) ⇄ NH3(g) + H2S(g)
An equilibrium mixture of this reaction at a certain temperature has [NH3] = [H2S ] =
0.78 M. What is Kc for this reaction? - ANSWER 0.61
Once equilibrium has been established: - ANSWER the reactant and product
concentrations do not change.
Which ion is basic when dissolved in water?
a. Mg2+
b. CN-
c. NO3-
d. NH4+ - ANSWER b. CN-
What is [H3O+] for a solution of pH = 2.22? - ANSWER 6.0 x 10-3 M
How does the Kb of a weak base change as a solution of it is made more
concentrated? - ANSWER It does not change.
What an insoluble salt is put in water, an equilibrium is established between: -
ANSWER the solid salt and its ions.
Methylamine is a weak base. What can we say about the reaction of this base with
water? - ANSWER ∆G > 0, K <1
Which of the following results in a ∆S,universe which is greater than 0? - ANSWER
the melting of ice at 298.15K
Which of the following metals with dissolve in 1.0 M HCl?
a. Ag
b. Au
c. None of the answers are correct
d. Cu - ANSWER c. None of the answers are correct
In a voltaic cell, what would happen if there was no salt bridge? - ANSWER There
would be no current.
The connection between ∆Gº and Eºcell is given by: ∆Gº = -nFEºcell
Consider the reaction:
Fe2+(aq) + 2Li(s) → Fe(s) + 2Li+(aq)
What is n for this reaction? - ANSWER 2
For a particular reaction at 298.15 K, ∆Hº = 23.2 kJ and ∆Sº is 134 J/K. What can we
say about this reaction? - ANSWER It is nonspontaneous at low temperatures but
becomes spontaneous at higher temperatures.
