CHM142 Exam 2 Review 2024/2025 with
Correct Answers | 2025 LATEST
UPDATED.
Which of the following plots is linear for a second-order reaction?
ln[A] versus t
[A]-1 versus t
[A] versus t
[A] versus t-1
[A]-1 versus t-1
[A]-1 versus t
The reaction
2N2O(g) → 2N2(g) + O2(g)
is a first-order reaction. If the initial concentration N2O is equal to 0.372 M and the rate constant
is 7.54 x 10-3 M s-1, what will the concentration be after 11.5 s?
0.341 M
The half-life for the first-order reaction
A(g) → B(g) + C(g)
is 115 s at an initial concentration of A of 0.286 M. How long will it take for 69.0% of A to react?
194 s
The rate constant for the reaction
2NO2(g) → 2NO(g) + O2(g)
is 0.17 M-1 s-1. What is the half-life for this reaction when the initial concentration of NO2 is
0.0640 M?
92 s
The dependence of rate constants on temperature is given by the Arrhenius equation
k = Ae-Ea/RT .
Under what conditions will k have the largest value?
Ea = 65 kJ/mol; T = 400 ºC
, The activation energy for the reaction
2HI(g) → H2(g) + I2(g)
is 184.0 kJ/mol. If the rate constant for this reaction is 2.70 x 10-4 M-1 s-1 at 327.0 ºC what
would be the rate constant at 352.0 ºC?
1.2 x 10-3 M^-1 s^-1
The reaction rates of many spontaneous reactions are actually very slow. Which of the following
is the best explanation for this observation?
- Such reactions are endothermic.
- Such reactions have extremely small equilibrium constants.
- Such reactions are exothermic.
- Such reactions have extremely large equilibrium constants.
- Such reactions have large activation energies.
Such reactions have large activation energies
The rate law for a decomposition of H2O2 in an aqueous solution that contains iodide ions, I-
(aq), is
Rate = k[H2O2][I-].
Which of the following elementary reactions could be the rate-determining step?
H2O2(aq) + I-(aq) → H2O(l) + OI-(aq)
H2O2(aq) → H2O(l) + O(g)
H2O2(aq) + H+(aq) + I-(aq) → H2O(l)
+ HOI(aq)
2H2O2(aq) → 2H2O(l) + O2(g)
H2O2(aq) + 2I-(aq) → 2OH-(aq) + I2(s)
H2O2(aq) + I-(aq) → H2O(l) + OI-(aq)
Which is the correct equilibrium constant Kp for the following reaction?
Na2CO3(s) + SO2(g) + (1/2)O2(g) ⇌ Na2SO4(s) + CO2(g)
Kp = PCO2 / [ PSO2 · (PO2)^1/2 ]
The value of Kc for the following reaction is 3.57 at 900.0 ºC.
CH4(g) + 2H2S(g) ⇌ CS2(g) + 4H2(g)
What is the value of Kp at this temperature?
3.3 x 10^4
Consider the two gaseous equilibria and the associated KP values
Correct Answers | 2025 LATEST
UPDATED.
Which of the following plots is linear for a second-order reaction?
ln[A] versus t
[A]-1 versus t
[A] versus t
[A] versus t-1
[A]-1 versus t-1
[A]-1 versus t
The reaction
2N2O(g) → 2N2(g) + O2(g)
is a first-order reaction. If the initial concentration N2O is equal to 0.372 M and the rate constant
is 7.54 x 10-3 M s-1, what will the concentration be after 11.5 s?
0.341 M
The half-life for the first-order reaction
A(g) → B(g) + C(g)
is 115 s at an initial concentration of A of 0.286 M. How long will it take for 69.0% of A to react?
194 s
The rate constant for the reaction
2NO2(g) → 2NO(g) + O2(g)
is 0.17 M-1 s-1. What is the half-life for this reaction when the initial concentration of NO2 is
0.0640 M?
92 s
The dependence of rate constants on temperature is given by the Arrhenius equation
k = Ae-Ea/RT .
Under what conditions will k have the largest value?
Ea = 65 kJ/mol; T = 400 ºC
, The activation energy for the reaction
2HI(g) → H2(g) + I2(g)
is 184.0 kJ/mol. If the rate constant for this reaction is 2.70 x 10-4 M-1 s-1 at 327.0 ºC what
would be the rate constant at 352.0 ºC?
1.2 x 10-3 M^-1 s^-1
The reaction rates of many spontaneous reactions are actually very slow. Which of the following
is the best explanation for this observation?
- Such reactions are endothermic.
- Such reactions have extremely small equilibrium constants.
- Such reactions are exothermic.
- Such reactions have extremely large equilibrium constants.
- Such reactions have large activation energies.
Such reactions have large activation energies
The rate law for a decomposition of H2O2 in an aqueous solution that contains iodide ions, I-
(aq), is
Rate = k[H2O2][I-].
Which of the following elementary reactions could be the rate-determining step?
H2O2(aq) + I-(aq) → H2O(l) + OI-(aq)
H2O2(aq) → H2O(l) + O(g)
H2O2(aq) + H+(aq) + I-(aq) → H2O(l)
+ HOI(aq)
2H2O2(aq) → 2H2O(l) + O2(g)
H2O2(aq) + 2I-(aq) → 2OH-(aq) + I2(s)
H2O2(aq) + I-(aq) → H2O(l) + OI-(aq)
Which is the correct equilibrium constant Kp for the following reaction?
Na2CO3(s) + SO2(g) + (1/2)O2(g) ⇌ Na2SO4(s) + CO2(g)
Kp = PCO2 / [ PSO2 · (PO2)^1/2 ]
The value of Kc for the following reaction is 3.57 at 900.0 ºC.
CH4(g) + 2H2S(g) ⇌ CS2(g) + 4H2(g)
What is the value of Kp at this temperature?
3.3 x 10^4
Consider the two gaseous equilibria and the associated KP values
