Deck 14: Chemical Kinetics

Question 1

The reaction A + 2B → Products has the rate law, rate = k[A][B]³. If the concentration of B is doubled while that of A is unchanged, by what factor will the rate of reaction increase?

A) 2
B) 4
C) 6
D) 8
E) 9

Answer 1

8

Question 2

For the reaction BrO₃^- + 5Br^- + 6H⁺ → 3Br₂ + 3H₂O at a particular time, -Δ[BrO₃^-]/Δt = 1.5 × 10^{-2 M}/s. What is -Δ[Br^-]/Δt at the same instant?

A) 13 M/s
B) 7.5 × 10^{-2 M}/s
C) 1.5 × 10^{-2 M}/s
D) 3.0 × 10^-3 M/s
E) 330 M/s

Answer 2

7.5 × 10^{-2 M}/s

Question 3

Which equation best describes the average rate for the reaction shown? A(aq) + B(aq) → C(aq) + D(aq)

A)
B) rate = +Δ[B]/Δt
C) rate = -Δ[C]/Δt
D) rate = -Δ[A]/Δt
E)

Answer 3

rate = -Δ[A]/Δt

Question 4

What are possible units for the rate of a reaction?

A) L • mol^-1 • s^-1
B) L² • mol^-2 • s^-1
C) s^-1
D) s^-2
E) mol • L^-1 • s^-1

Question 5

For the reaction 3A(g) + 2B(g) → 2C(g) + 2D(g)
The following data were collected at constant temperature. Determine the correct rate law for this reaction.

A) Rate = k[A][B]
B) Rate = k[A][B]²
C) Rate = k[A]³[B]²
D) Rate = k[A]^1.5[B]
E) Rate = k[A]²[B]

Question 6

What is the name given for the study of how fast reactions take place?

A) Reaction rate
B) Activation energy
C) Chemical kinetics
D) Reactivity
E) Half-life

Question 7

Consider the following reaction 8A(g) + 5B(g) → 8C(g) + 6D(g)
If [C] is increasing at the rate of 4.0 mol L^-1 • s^-1, at what rate is [B] changing?

A) -0.40 mol L^-1• s^-1
B) -2.5 mol L^-1• s^-1
C) -4.0 mol L^-1• s^-1
D) -5.0 mol L^-1• s^-1
E) -6.4 mol L^-1• s^-1

Question 8

The reaction A + 2B → Products was found to follow the rate law: rate = k[A]²[B]. Predict by what factor the rate of reaction will increase when the concentration of A is doubled, the concentration of B is tripled, and the temperature remains constant.

A) 5
B) 6
C) 12
D) 18
E) None of these

Question 9

Consider the general reaction 5Br^-(aq) + BrO₃^-(aq) + 6H⁺(aq) → 3Br₂(aq) + 3H₂O(aq)
For this reaction, which is equal to Δ[Br₂]/Δt?

A) -Δ[H₂O]/Δt
B) 3Δ[BrO₃^-]/Δt
C) -5Δ[Br^-]/Δt
D) -0.6Δ[Br^-]/Δt
E) None of these choices is correct.

Question 10

For the reaction A + 2B → C, which expression is correct?

A) Δ[C]/Δt = Δ[A]/Δt
B) Δ[C]/Δt = 2Δ[B]/Δt
C) Δ[C]/Δt = -2Δ[B]/Δt
D) Δ[C]/Δt = -½Δ[B]/Δt
E) Δ[C]/Δt = -½Δ[A]/Δt

Question 11

The reaction A + 2B → Products has been found to have the rate law, rate = k[A][B]². While holding the concentration of A constant, the concentration of B is increased to three times its initial value. By what factor does the rate of reaction increase?

A) 3
B) 6
C) 9
D) 27
E) 30

Question 12

For the overall chemical reaction shown below, which one of the following statements can be rightly assumed? 2H₂S(g) + O₂(g) → 2S(s) + 2H₂O(l)

A) The reaction is third-order overall.
B) The reaction is second-order overall.
C) The rate law is: rate = k[H₂S]² [O₂].
D) The rate law is: rate = k[H₂S] [O₂].
E) The rate law cannot be determined from the information given.

Question 13

For the reaction C₆H₁₄(g) → C₆H₆(g) + 4H₂(g), ΔP(H₂)/Δt was found to be 2.5 × 10^-2 atm/s, where ΔP(H₂) is the change in pressure of hydrogen. Determine ΔP(C₆H₁₄)/Δt for this reaction at the same time.

A) 2.5 × 10^-2 atm/s
B) -6.3 × 10^-3 atm/s
C) -2.5 × 10^-2 atm/s
D) 0.10 atm/s
E) 6.3 × 10^-3 atm/s

Question 14

For the hypothetical reaction A + 3B → 2C, the rate should be expressed as

A) rate = Δ[A]/Δt.
B) rate = -Δ[C]/Δt.
C) rate = -3(Δ[B]/Δt).
D) rate = (1/2)(Δ[C]/Δt).
E) rate = (1/3)(Δ[B]/Δt).

Question 15

For the reaction A(g) + 2B(g) → 2C(g) + 2D(g)
The following data were collected at constant temperature. Determine the correct rate law for this reaction.

A) Rate = k[A][B]
B) Rate = k[A]²[B]
C) Rate = k[A][B]²
D) Rate = k[A]
E) Rate = k[A]³

Question 16

What is the rate expression for the production of X, which is a gas, at constant volume?

A) rate = P_gVΔ[X]/RΔt
B) rate = -TΔ[X]/P_gVΔt
C) rate = -P_gV(Δ[X]/TΔt)
D) rate = (1/RT)(ΔP_X/Δt)
E) rate = (1/RΔP_X)(VT/Δt)

Question 17

The reaction A + 2B → Products was found to have the rate law, rate = k[A][B]². Predict by what factor the rate of reaction will increase when the concentration of A is doubled and the concentration of B is also doubled.

A) 2
B) 4
C) 6
D) 8
E) 9

Question 18

For the following reaction, ΔP(C₆H₁₄)/Δt was found to be -6.2 × 10^-3 atm/s. C₆H₁₄(g) → C₆H₆(g) + 4H₂(g)
Determine ΔP(H₂)/Δt for this reaction at the same time.

A) 6.2 × 10^-3 atm/s
B) 1.6 × 10^-3 atm/s
C) 2.5 × 10^-2 atm/s
D) -1.6 × 10^-3 atm/s
E) -2.5 × 10^-2 atm/s

Question 19

The compound RX₃ decomposes according to the equation 3RX₃ → R + R₂X₃ + 3X₂
In an experiment the following data were collected for the decomposition at 100°C. What is the average rate of change of RX₃ over the entire experiment?

A) -0.011 mol • L^-1 • s^-1
B) -0.019 mol • L^-1 • s^-1
C) -0.044 mol • L^-1 • s^-1
D) -0.049 mol • L^-1 • s^-1
E) -0.069 mol • L^-1 • s^-1

Question 20

Consider the reaction 2NH₃(g) → N₂(g) + 3H₂(g)
If the rate Δ[H₂]/Δt is 0.030 mol L^-1 • s^-1, what is Δ[NH₃]/Δt?

A) -0.045 mol L^-1• s^-1
B) -0.030 mol L^-1• s^-1
C) -0.020 mol L^-1• s^-1
D) -0.010 mol L^-1• s^-1
E) None of these choices is correct.

Question 21

Which is the correct unit for a first-order rate constant?

A) s^-1
B) M • s^-1
C) M • s
D) M -1 • s^-1
E) M -2 • s^-1

Question 22

The data below were determined for the reaction S₂O₈^2-(aq) + 3I^-(aq) → 2SO₄^2-(aq) + I₃^-(aq). Which rate law is consistent with the experimental data for this reaction?

A) rate = k[S₂O₈^2- ][I ^-]³
B) rate = k[S₂O₈^2-]
C) rate = k[S₂O₈^2-]²[I ^-]²
D) rate = k[I ^-]
E) rate = k[S₂O₈^2-][I ^-]

Question 23

The following initial rate data apply to the reaction F₂(g) + 2Cl₂O(g) → 2FClO₂(g) + Cl₂(g). Which of the following is the rate law for this reaction?

A) rate = k[F₂]²[Cl₂O]⁴
B) rate = k[F₂]²[Cl₂O]
C) rate = k[F₂][Cl₂O]
D) rate = k[F₂][Cl₂O]²
E) rate = k[F₂]²[Cl₂O]²

Question 24

Ammonium ion (NH₄⁺) reacts with nitrite ion (NO₂^-) to yield nitrogen gas and liquid water. The following initial rates of reaction have been measured for the given reactant concentrations. Which of the following is the rate law (rate equation) for this reaction?

A) rate = k [NH₄⁺] [NO₂^-]⁴
B) rate = k [NH₄⁺] [NO₂^-]
C) rate = k [NH₄⁺] [NO₂^-]²
D) rate = k [NH₄⁺]² [NO₂^-]
E) rate = k [NH₄⁺]^1/2 [NO₂^-]^1/4

Question 25

What statement below best describes the graph representing the integrated first-order rate law?

A) A plot of [A]_t vs. t yields a straight line with a negative slope equal to -k.
B) A plot of 1/[A]_t vs. t yields a straight line with a negative slope equal to k.
C) A plot of ln[A]_t vs. t yields a straight line with a positive slope equal to -k.
D) A plot of ln[A]_t vs. t yields a straight line with a negative slope equal to -k.
E) A plot of 1/[A]_t vs. t yields a straight line with a positive slope equal to k.

Question 26

Which of the following is the correct unit for a second-order rate constant?

A) s^-1
B) M • s^-1
C) M • s
D) M ^-1 • s^-1
E) M ^-2 • s^-1

Question 27

A certain reaction A → products is second order in A. If this reaction is 85% complete in 12 minutes, how long would it take for the reaction to be 15% complete?

A) 110 s
B) 27 s
C) 62 s
D) 130 s
E) 22 s

Question 28

A certain first-order reaction A → B is 25% complete in 42 min at 25°C. What is its rate constant?

A) 6.8 × 10^-3 min^-1
B) 8.3 × 10^-3 min^-1
C) 3.3 × 10^-2 min^-1
D) -3.3 × 10^-2 min^-1
E) 11 min^-1

Question 29

Which is the correct unit for a zeroth-order rate constant?

A) s^-1
B) M • s^-1
C) M • s
D) M^-1 • s^-1
E) M^-2 • s^-1

Question 30

When the reaction A → B + C is studied, a plot of ln[A]_t vs. time gives a straight line with a negative slope. What is the order of the reaction with respect to A?

A) Zero
B) First
C) Second
D) Third
E) More information is needed to determine the order.

Question 31

A certain first-order reaction A → B is 25% complete in 42 min at 25°C. What is the half-life of the reaction?

A) 21 min
B) 42 min
C) 84 min
D) 120 min
E) 101 min

Question 32

Sulfuryl chloride, SO₂Cl₂(g), decomposes at high temperature to form SO₂(g) and Cl₂(g). The rate constant at a certain temperature is 4.68 × 10^-5 s^-1. What is the order of the reaction?

A) Zero
B) First
C) Second
D) Third
E) More information is needed to determine the overall order.

Question 33

The first-order reaction SO₂Cl₂→ SO₂ + Cl₂ is 10% complete in 80. min. How long would it take for the reaction to be 95% complete?

A) 1.8 min
B) 104 min
C) 530 min
D) 2300 min
E) 990 min

Question 34

A first-order reaction has a rate constant of 3.00 × 10^-3 s^-1. The time required for the reaction to be 75.0% complete is

A) 95.8 s.
B) 462 s.
C) 231 s.
D) 201 s.
E) 41.7 s.

Question 35

At 25°C the rate constant for the first-order decomposition of a pesticide solution is 6.40 × 10^-3 min^-1. If the starting concentration of pesticide is 0.0314 M, what concentration will remain after 62.0 min at 25°C?

A) 1.14 × 10^{-1 M}
B) 47.4 M
C) 1.25 ×10^{-2 M}
D) 2.11 × 10^-2 M
E) 2.68 × 10^-2 M

Question 36

What statement below best describes the graph representing the integrated second-order rate law?

A) A plot of [A]_t vs. t yields a straight line with a negative slope equal to -k.
B) A plot of 1/[A]_t vs. t yields a straight line with a negative slope equal to k.
C) A plot of ln[A]_t vs. t yields a straight line with a positive slope equal to -k.
D) A plot of ln[A]_t vs. t yields a straight line with a negative slope equal to -k.
E) A plot of 1/[A]_t vs. t yields a straight line with a positive slope equal to k.

Question 37

The rate constant for a reaction is 4.65 L • mol^-1 • s^-1. What is the overall order of the reaction?

A) Zero
B) First
C) Second
D) Third
E) More information is needed to determine the overall order.

Question 38

A first-order reaction has a rate constant of 7.5 × 10^-3 s^-1. The time required for the reaction to be 60% complete is

A) 3.8 × 10^-3 s.
B) 6.9 × 10^-3 s.
C) 68 s.
D) 120 s.
E) 130 s.

Question 39

For the reaction 2A + B + 2C → D + E
The following initial rate data were collected at constant temperature. What is the correct rate law for this reaction?

A) Rate = k [A][B][C]
B) Rate = k [A]²[B][C]
C) Rate = k [A]²[B][C]^-1
D) Rate = k [A][B]²[C]^-1
E) None of these choices is correct.

Question 40

It takes 42.0 min for the concentration of a reactant in a first-order reaction to drop from 0.45 M to 0.32 M at 25°C. How long will it take for the reaction to be 90% complete?

A) 13.0 min
B) 86.0 min
C) 137 min
D) 222 min
E) 284 min

Question 41

For the reaction X + Y → Z, the reaction rate is found to depend only upon the concentration of X. A plot of 1/X versus time gives a straight line. What is the rate law for this reaction?

A) rate = k [X]
B) rate = k [X]²
C) rate = k [X][Y]
D) rate = k [X]²[Y]
E) rate = k [X]²/[Y]

Question 42

For the chemical reaction A → B + C, a plot of [A]_t versus time is found to give a straight line with a negative slope. What is the order of reaction with respect to A?

A) Zeroth
B) First
C) Second
D) Third
E) Such a plot cannot reveal the order of the reaction.

Question 43

Nitric oxide gas (NO) reacts with chlorine gas according to the equation NO + Cl₂ → NOCl.
The following initial rates of reaction have been measured for the given reagent concentrations. Which of the following is the rate law for this reaction?

A) rate = k[NO]
B) rate = k[NO][Cl₂]^1/2
C) rate = k[NO][Cl₂]
D) rate = k[NO]²[Cl₂]
E) rate = k[NO]²[Cl₂]²

Question 44

Tetrafluoroethylene, C₂F₄, can be converted to octafluorocyclobutane, which can be used as a refrigerant or an aerosol propellant. A plot of 1/[C₂F₄] vs. time gives a straight line with a slope of 0.0448 L •mol^-1 • s^-1. What is the rate law for this reaction?

A) Rate = 0.0448 (L • mol^-1 • s^-1)[C₂F₄]
B) Rate = 22.3 (mol • L^-1 • s)[C₂F₄]
C) Rate = 0.0448 (L • mol^-1 • s^-1)[C₂F₄]²
D) Rate = 22.3 (mol • L^-1 • s)[C₂F₄]²
E) Rate = 0.0448 s^-1 [C₂F₄]

Question 45

For the chemical reaction A → C, a plot of 1/[A]_t versus time was found to give a straight line with a positive slope. What is the order of reaction?

A) Zeroth
B) First
C) Second
D) Third
E) Such a plot cannot reveal the order of the reaction.

Question 46

Cyclopropane is converted to propene in a first-order process. The rate constant is 5.4 × 10^-2 h^-1. If the initial concentration of cyclopropane is 0.150 M, what will its concentration be after 22.0 hours?

A) 0.046 M
B) 0.11 M
C) 0.13 M
D) 0.49 M
E) 0.054 M

Question 47

For a zeroth-order reaction, if the concentration of reactant A is plotted vs. time, which corresponds to the slope of this plot?

A) 1/[A]
B) k
C) 1/k
D) ln[A]
E) -k

Question 48

The thermal decomposition of acetaldehyde, CH₃CHO → CH₄ + CO, is a second-order reaction. The following data were obtained at 518°C. Calculate the rate constant for the decomposition of acetaldehyde from the above data.

A) 2.2 × 10^-3 s^-1
B) 0.70 mmHg • s^-1
C) 2.2 × 10^-3 /mmHg • s^-1
D) 6.7 × 10^-6 /mmHg • s^-1
E) 5.2 × 10^-5 /mmHg • s^-1

Question 49

Sucrose decomposes to fructose and glucose in acid solution. When ln [sucrose] is plotted vs. time, a straight line with slope of -0.208 h^-1 results. What is the rate law for the reaction?

A) Rate = (0.208 h^-1)[sucrose]²
B) Rate = (0.208 h^-1)[sucrose]
C) Rate = (0.0433 h)[sucrose]²
D) Rate = (0.0433 h)[sucrose]
E) Rate = (0.208 mol L^-1 • h^-1)[sucrose]⁰

Question 50

Consider the reaction 2NOBr(g) → 2NO(g) + Br₂(g). The initial rate of the reaction was measured for three different concentrations of NOBr, given below. Based on the initial rate data above, what is the value of the rate constant?

A) 0.0360 L • mol^-1 • s^-1
B) 0.800 L • mol^-1 • s^-1
C) 1.25 L • mol^-1 • s^-1
D) 27.8 L • mol^-1 • s^-1
E) 0.0360 s^-1

Question 51

What is defined as the minimum amount of energy required to initiate a chemical reaction?

A) Collision energy
B) Effective collision energy
C) Reaction energy
D) Activation energy
E) Rate energy

Question 52

A study of the decomposition reaction 3RX₂ → 3R + 6X yields the following initial rates. What is the rate constant for the reaction?

A) 0.0103 L • mol^-1 • s^-1
B) 0.263 L • mol^-1 • s^-1
C) 0.571 L • mol^-1 • s^-1
D) 1.17 L • mol^-1 • s^-1
E) 1.75 L • mol^-1 • s^-1

Question 53

What is the activation energy for a reaction if k = 1.89 × 10^-8 s^-1 at 540. K and k = 2.45 × 10^-7 s^-1 at 601 K?

A) 113 kJ/mol
B) 83 kJ/mol
C) 410 kJ/mol
D) 280 kJ/mol
E) 580 kJ/mol

Question 54

A) Zeroth
B) First
C) Second
D) Third
E) Such a plot cannot reveal the order of the reaction.

Question 55

The rate law for the rearrangement of CH₃NC to CH₃CN at 800 K is rate = (1300 s^-1)[CH₃NC]. What is the half-life for this reaction?

A) 7.69 × 10^-4 s
B) 5.3 × 10^-4 s
C) 1.9 × 10^-3 s
D) 520 s
E) 1920 s

Question 56

A reaction has the following rate law: rate = k[A][B]²
In experiment 1, the concentrations of A and B are both 0.10 mol • L^-1; in experiment 2, the concentrations are both 0.30 mol • L^-1. If the temperature stays constant, what is the value of the ratio, rate(2)/rate(1)?

A) 3.0
B) 6.0
C) 9.0
D) 18
E) 27

Question 57

The reaction 2NO₂(g) → 2NO(g) + O₂(g) is suspected to be second order in NO₂. Which of the following kinetic plots would be the most useful to confirm whether or not the reaction is second order?

A) A plot of [NO₂]^-1 vs. t
B) A plot of ln [NO₂] vs. t
C) A plot of [NO₂] vs. t
D) A plot of ln [NO₂]^-1 vs. t
E) A plot of [NO₂]² vs. t

Question 58

The rate law for the reaction 3A → 2B is rate = k[A] with a rate constant of 0.0447 h^-1. What is the half-life of the reaction?

A) 0.0224 h
B) 0.0645 h
C) 15.5 h
D) 22.4 h
E) 44.7 h

Question 59

Ammonium cyanate (NH₄CNO) reacts to form urea (NH₂CONH₂). At 65°C the rate constant, k, is 3.60 L • mol^-1 • s^-1. What is the rate law for this reaction?

A) Rate = (3.60 L • mol^-1 • s^-1)[NH₄CNO]
B) Rate = (3.60 L • mol^-1 • s^-1)[NH₄CNO]²
C) Rate = (0.28 mol • L^-1 • s^-1)[NH₄CNO]
D) Rate = (0.28 mol • L^-1 • s^-1)[NH₄CNO]²
E) Rate = (3.60 L • mol^-1 • s^-1)[NH₂CONH₂]^-1

Question 60

When the reaction A → B + C is studied, a plot 1/[A]_t vs. time gives a straight line with a positive slope. What is the order of the reaction with respect to A?

A) Zero
B) First
C) Second
D) Third
E) More information is needed to determine the order.

Question 61

What is the half-life for a first-order reaction?

A)
B)
C)
D)
E)

Question 62

What is the half-life for a first-order reaction?

A) t_1/2 = k
B) t_1/2 = 1/k[A]_o
C) t_1/2 = 0.693/k[A]_o
D) t_1/2 = [A]_o/2k
E) t_1/2 = 0.693/k

Question 63

The rate constant for the reaction 3A → 4B is 6.00 × 10^-3 L • mol^-1 • min^-1. How long will it take the concentration of A to drop from 0.75 M to 0.25 M?

A) 2.2 × 10^-3 min
B) 5.5 × 10^-3 min
C) 180 min
D) 440 min
E) 5.0 × 10²min

Question 64

For a zeroth-order reaction, if the concentration of reactant A is plotted vs. time, which corresponds to the slope of this plot?

A) 1/[A]
B) k
C) 1/k
D) ln[A]
E) -k

Question 65

Carbon-14 is a radioactive isotope which decays with a half-life of 5730 years. What is the first-order rate constant for its decay?

A) 5.25 × 10^-5 yr^-1
B) 1.21 × 10^-4 yr^-1
C) 1.75 × 10^-4 yr^-1
D) 3.49 × 10^-4 yr^-1
E) 3.97 × 10³ yr^-1

Question 66

What is the integrated rate law for a zeroth-order reaction?

A) rate = k[A]_t
B)
C)
D)
E)

Question 67

What is the half-life for a second-order reaction?

A) t_1/2 = k
B) t_1/2 = 1/k[A]_o
C) t_1/2 = 0.693/k[A]_o
D) t_1/2 = [A]_o/2k
E) t_1/2 = 0.693/k

Question 68

What is the half-life for a zeroth-order reaction?

A) t_1/2 = k
B) t_1/2 = 1/k[A]_o
C) t_1/2 = 0.693/k[A]_o
D) t_1/2 = [A]_o/2k
E) t_1/2 = 0.693/k

Question 69

What is the half-life for a second-order reaction?

A)
B)
C)
D)
E)

Question 70

Butadiene, C₄H₆ (used to make synthetic rubber and latex paints), dimerizes to C₈H₁₂ with a rate law of rate = 0.014 L/mol• s [C₄H₆]². What will be the concentration of C₄H₆ after 3.0 hours if the initial concentration is 0.025 M?

A) 0.0052 M
B) 0.024 M
C) 43 M
D) 190 M
E) 0.0000 M

Question 71

The reaction CH₃NC(g) → CH₃CN(g) is first order with respect to methyl isocyanide, CH₃NC. If it takes 10.3 minutes for exactly one quarter of the initial amount of methyl isocyanide to react, what is the rate constant in units of min^-1?

A) -0.135 min^-1
B) 0.0279 min^-1
C) 0.089 min^-1
D) 0.135 min^-1
E) 35.8 min^-1

Question 72

The rate law for the reaction 3A → C is rate = 4.36 × 10^-2 L• mol^-1 • h^-1[A]². What is the half-life for the reaction if the initial concentration of A is 0.250 M?

A) 0.0109 h
B) 0.0629 h
C) 15.9 h
D) 23.9 h
E) 91.7 h

Question 73

For a second-order reaction, if [A]^-1 is plotted vs. time, which corresponds to the slope of this plot?

A) 1/[A]
B) k
C) 1/k
D) ln[A]
E) -k

Question 74

The activation energy for the following reaction is 60. kJ/mol. Sn²⁺ + 2Co³⁺ → Sn⁴⁺ + 2Co²⁺
By what factor will the rate constant increase when the temperature is raised from 10°C to 28°C? (R = 8.314 J/mol• K)

A) 1.002
B) 4.6
C) 5.6
D) 2.8
E) 696

Question 75

What is the slope of a plot of ln k vs. 1/T for the Arrhenius equation k = Ae^-(E_a/RT)?

A) A
B) -k
C) -E_a/R
D) k
E) E_a

Question 76

What is the integrated rate law for a second-order reaction?

A) rate = k[A]_t
B)
C)
D)
E)

Question 77

The radioactive isotope tritium decays with a first-order rate constant k of 0.056 yr^-1. What fraction of the tritium initially in a sample is still present 30. years later?

A) 0.19
B) 0.60
C) 0.15
D) 2.8 × 10^-38
E) 0.81

Question 78

A reactant R is being consumed in a first-order reaction. What fraction of the initial R is consumed in 4.0 half-lives?

A) 0.94
B) 0.88
C) 0.75
D) 0.13
E) 0.063

Question 79

What rate constant can be determined from only the half-life of a reaction?

A) Zeroth
B) First
C) Second
D) Third
E) The rate constant cannot be determined using only a rate constant for any reaction.

Question 80

What is the integrated rate law for a first-order reaction?

A) rate = k[A]_t
B)
C)
D)
E)