Chemistry Chapter 17 Study
Given the rate law and table below, what are the values of m and n? Rate= k[A]m[B]n [A](M) [B](m) Rate (M/s)
D) m = 0, n = 1
Identify the molecularity of the elementary reaction below: 2 A + B → C + 2 D A) Unimolecular B) Bimolecular C) Termolecular D) Cannot be determined from given mechanism
NOT B) Bimolecular [not sure correct answer, probably C] {The molecularity of an elementary step is determined by how many reactants are involved in the reaction.}
The initial concentration of a reactant in a first order reaction is 0.860 M. What will be its concentration after 4 half-lives have passed?
0.0538 M
A reaction has a rate law of Rate = (1.25 M⁻¹s⁻¹)[A][B]. What is the rate of the reaction if [A] = 0.525 M and [B] = 0.280 M?
0.184 M/s
What is the rate at which Br⁻(aq) disappears in the reaction below if the rate of disappearance of BrO₃⁻(aq) is 0.050 M/s? BrO₃⁻ + 5 Br⁻ + 6 H⁺ → 3 Br₂ + 3H₂O
0.25 M/s
What is the concentration of A after 10.5 minutes for the reaction A → Products when the initial concentration of A is 0.750 M? (k = 0.0451 M⁻¹min⁻¹)
0.553 M
Consider the radioisotope ²⁴⁰Pu (half life = 6.56 × 10³ years). What is the first order rate constant for ²⁴⁰Pu?
1.06 × 10⁻⁴ 1/years
The radioisotope ¹⁴C (half life = 5730 years) is used for carbon dating. What is the first order rate constant for ¹⁴C?
1.21 × 10⁻⁴ 1/years
How long will it take for the concentration of A to decrease from 0.500 M to 0.140 M in the first-order reaction A → B? (k = 0.800 s⁻¹)
1.59 s
How long will it take for the concentration of A to decrease from 1.25 M to 0.305 for the second order reaction A → Products? (k = 1.52 M⁻¹min⁻¹)
1.63 min
A substance decomposes with a rate constant of 9.05 × 10⁻⁴ s⁻¹. How long does it take for 15.0% of the substance to decompose?
180 s
If a reaction is first order with a rate constant of 0.0450 s⁻¹, how much time is required for 65% of the initial quantity of reactant to be consumed?
23.3 s
What percentage of reactant will remain after 120 seconds if the half-life is 60 seconds for a first-order reaction?
25 %
An experimental plot of ln(k) vs. 1/T is obtained in lab for a reaction. The slope of the best-fit line for the graph is -3335 K. What is the value of the activation energy for the reaction in kJ/mol?
27.73 kJ/mol
What is the activation energy of a reaction if it has the following rate constants? Rate Constant Temperature 6.20 x 10^-4 s^-1 700 K 2.39 x 10^-2 s^-1 760 K
270 kJ/mol
A first order reaction initially contains 4.85 × 10²⁰ molecules. If the reaction has a half-life of 20.0 minutes, how many molecules remain unreacted after 80.0 minutes?
3.03 × 10¹⁹ molecules
What is the half-life for a particular reaction if the rate law is rate = (1211 M⁻¹*min⁻¹)[A]² and the initial concentration of A is 0.250 M?
3.30 × 10⁻³ min
How long will it take for the concentration of A to decrease from 0.910 M to 0.315 for the reaction A → Products? (k = 0.153 M/s)
3.89 s
What is the overall reaction order for the following rate law: Rate = k[A][B][C]²
4
For the reaction 2 A + 4 B → 2 C + 4 D, what is the absolute magnitude of the rate of change for [B] when [C] is increasing at 2.0 M/s?
4.0 M/s
For the reaction 3 A + 4 B → 2 C + D, what is the magnitude of the rate of change for [C] when [D] is increasing at 2.7 M/min?
5.4 M/min
What is the rate of reaction in terms of C in the following reaction: A + B → 2 C. A) +0.5∆[C]/∆t B) +∆[C]/∆t C) +2∆[C]/∆t D) -0.5∆[C]/∆t E) -∆[C]/∆t
A) +0.5∆[C]/∆t
Trial [B]O [A]o Initial Rate (M/min) A) Rate = k[A] B) Rate = K[A] C) Rate = K[A][B] D) Rate = k[A]*[B] E) Rate = kAIB)
A) Rate = k[A]
A reaction was shown to have an increasing half-life with increasing concentration of reactant. What order is this reaction? A) Zero B) First C) Second D) None of these because half-life is always concentration dependent E) Cannot be determined from this information
A) Zero
What order of reaction has a linear curve when plotting concentration versus time? A) Zeroth B) First C) Second D) Third E) All reaction orders have a linear curve when plotted
A) Zeroth
Given the reaction A + 2 B → 3 C, the rate of appearance of C is also equal to which of the following? A) +3/2∆[B]/∆t B) -3/2∆[B]/∆t C) +∆[A]/∆t D) -1/3∆A/∆t E) -∆[B]/∆t
B) -3/2∆[B]/∆t
What is the effect on k as the activation energy for a reaction increases? A) Increases B) Decreases C) Stays the same D) Not enough info
B) Decreases
What order of reaction has a half life equation of t½ = 0.693/k? A) Zeroth B) First C) Second D) All reactions have the same half-life equation
B) First
What is the rate law for the reaction A + B → C + D given the experimental data for four trials of initial rate?
B) Rate = k[A]²[B]
What is the molecularity of step 1 in the proposed mechanism? Step 1 CI + O3 → CIO + O2 Step 2 CIO + O3 + CI+ 202 A) unimolecular B) bimolecular
B) bimolecular
The following reaction 2 NO(g) + O₂(g) → 2 NO₂(g) was found to be first order in each of the two reactants and second order overall. The rate law is therefore A) rate = k[NO]²[O₂] B) rate = k[NO][O₂] C) rate = k[NO₂]² - [NO]² - [O₂] D) rate = k[NO]²[O₂]² E) rate = k([NO][O₂])⁻²
B) rate = k[NO][O₂]
If a plot of 1/[A] versus time produces a straight line with a positive slope for the reaction A → B + C, what is the order of the reaction? A) Zero B) First C) Second D) Third E) Cannot determine order from this information
C) Second
What is the order of the reaction A → B given the plot shown?
C) Second
Which equation is used to determine the amount of time required for the initial concentration to decrease by 45% if the rate constant has units of s⁻¹? A) t = ln 2/k B) Rate = k[A] C) ln([A]/[A]₀) = -kt D) [A] = [A]₀ - kt E) 1/[A] = 1/[A]₀ + kt
C) ln([A]/[A]₀) = -kt
What is the rate law for the proposed mechanism? H2(g) + 2NO(g) + N2O(g) + H2O(g) Step 1 (slow) N2O(g) + H2(g) N2(g) + H2O(g) Step 2 (fast)
C) rate = k[H₂][NO]²
Given the following elementary reaction what is the molecularity? A + 2B → AB₂ A) unimolecular B) bimolecular C) termolecular D) tetramolecular E) Cannot be determined with the given information
C) termolecular
What is the molecularity of the elementary step from a mechanism given below? H⁺ + H₂O₂ + Br⁻ → H₂O + HBrO A) unimolecular B) bimolecular C) termolecular D) Cannot be determined from given mechanism
C) termolecular
For the reaction 2 A + 3 B → 4 D + 5 E, how is the rate of reaction expressed in terms of rate of disappearance of B? A) ∆[B]/∆t B) -∆B/∆t C) +1/3∆[B]/∆t D) -1/3∆[B]/∆t E) +3∆[B]/∆t
D) -1/3∆[B]/∆t
Considering the Arrhenius equation, what is the slope of a plot of ln k versus 1/T equal to? A) k B) -k C) Ea D) -Ea/R E) A
D) -Ea/R
How is a second-order half-life (t1/2) calculated? A) 0.693/k B) k/0.693 C) k D) 1/(k[A]₀) E) [A]₀/2k
D) 1/(k[A]₀)
The following reaction 2CO(g) + Br₂(g) → 2COBr(g) has the rate law, rate = k[CO] [Br₂]³. The overall order of this reaction is A) 1st B) 2nd C) 3rd D) 4th E) 0th
D) 4th
Using the information in the table, the rate law for the reaction 2 A(g) + B(g) → C(g) + D(g) is (version 2)
D) Rate = k[A]
Using the information in the table, the rate law for the reaction 2 A(g) + B(g) → C(g) + D(g) is
D) Rate = k[A][B]²
Considering the rate law, rate = k[A]²[B], which of the following statements is correct? A) The reaction is first order in A and second order overall. B) The reaction is first order in B and second overall. C) The reaction is second order in A and second order overall. D) The reaction is first order in B and third order overall. E) The reaction is second order in A and first order overall.
D) The reaction is first order in B and third order overall.
Catalysts increase reaction rates by _____ A) increasing the activation energy. B) increasing the enthalpy of reaction. C) decreasing the enthalpy of reaction. D) providing an alternate reaction mechanism with a lower activation energy. E) changing the value of the equilibrium constant.
D) providing an alternate reaction mechanism with a lower activation energy.
If the reaction X + 2 Y → XY₂ occurs by the proposed mechanism, what is the rate law? Step 1 X+Y=XY (slow) Step 2 XY + Y + XY2 (fast) A) rate = k[X] B) rate = k[Y] C) rate = k[Y]^2 D) rate = K[X][Y] E) rate = K[X][Y]^2
D) rate = k[X][Y]
Using the information in the table, the value of the rate constant for the reaction A(g) + 3 B(g) → C(g) + 2 D(g) is
E) 0.722 M⁻¹min⁻¹
The Haber Process: N₂ + 3H₂ → 2NH₃ is an important industrial route for the production of ammonia. However, the reaction does not occur fast enough at room temperature to be useful. What could be done to increase the rate of this reaction the most? A) Decrease the temperature B) Add a catalyst C) Increase the temperature D) Decrease the temperature and add a catalyst E) Add a catalyst and increase the temperature
E) Add a catalyst and increase the temperature
In the provided reaction profile, the black line represents the pathway of the reaction of A and B going to AB. The red line represents the pathway when catalyst K is added. What is catalyst K doing in the reaction? A) Lowering the enthalpy of the reaction B) Lowering the activation energy of the reaction C) Changing the mechanism of the reaction D) Both A and B E) Both B and C
E) Both B and C
Which of the following statements is correct concerning the reaction 2 A + B → 2 C + 2 D? A) The reaction is second order overall. B) The reaction is third order overall. C) The rate is equal to k[A]²[B]. D) The rate is equal to k[A][B]. E) It is not possible to determine the overall order nor the rate law from the given information.
E) It is not possible to determine the overall order nor the rate law from the given information.
Which species has the greatest rate of appearance in the reaction below? 2 H₂S + O₂ → 2 S + 2 H₂O A) H₂S B) O₂ C) S D) H₂O E) S and H₂O have identical rates
E) S and H₂O have identical rates