Concept #1: Understanding Average or General Rate.

**General** or **Average Rate** is the change in the concentration of a compound over a period of time.

Example #1: The following equation shows the production of NO and H_{2}O by oxidation of ammonia.

**4** NH_{3} (g) + **5** O_{2 }(g) → **4** NO (g) + **6** H_{2}O (l)

**a.** What is the average rate of each compound in the balanced equation?

Example #2: b) What is the rate of NH_{3} in the reaction between 2 and 6 minutes at 40** ^{o}**C?

Example #3: c) Determine the instantaneous rate of the following reaction.

In a stoichiometry based question we are accustomed to doing a mole-to-mole comparison. Now in Chemical Kinetics, we will do instead a rate-to-rate comparison.

Example #4: The decomposition of dinitrogen pentoxide is described by the chemical equation:

2 N_{2}O_{5} (g) ---> 4 NO_{2} (g) + O_{2} (g)

If the ** rate of disappearance or decomposition **of O

Practice: The formation of alumina, Al_{2}O_{3}, can be illustrated by the reaction below: 4 Al (s) + 3 O_{2} (g) ----> 2 Al_{2}O_{3} (s). At 750 K it takes 267 seconds for the initial concentration of Al_{2}O_{3} to increase from 6.18 E-5 M to 5.11 E-4 M. What is the rate of Al?

The combustion of propanol, C3H7OH (l), to produce carbon dioxide and water vapor is a highly exothermic process
2 C3H7OH (l) + 9 O2 (g) → 6 CO2 (g) + 8 H2O (g)
The following data table shows the change in concentration of O 2 over time. Use this data to determine the rate of evolution of water vapor, H2O(g), in the reaction between 10 and 30 seconds.
Time in seconds Concentration of O2 (M)
0 2.48 x 10 -3
10 1.26 x 10 -3
20 8.98 x 10 -4
30 7.17 x 10 -4
40 6.32 x 10 -4
50 5.98 x 10 -4
60 5.71 x 10 -4
a. 2.73 x 10 -5
b. 2.41 x 10 -5
c. 4.83 x 10 -4
d. 3.05 x 10 -5
e. 6.11 x 10 -4

For the reaction given, the FeCl3 changes from 1.000 M to 0.444 M in the first 10 seconds.
Calculate the average rate in the first 10 seconds.
2 FeCl3 (s) → 2 Fe (s) + 3 Cl2 (g)
a. 0.0384 M/s
b. 0.210 M/s
c. 0.0278 M/s
d. 0.0874 M/s
e. 0.568 M/s

Consider the following hypothetical reaction
4A (g) + 2B (g) → 3C (g) + D (g)
Which of the following statement(s) is/are correct?
i. The rate B disappears is twice (2 times) the rate that D appears.
ii. The rate A disappears is twice (2 times) the rate that B disappears.
iii. The rate C appears is one third (1/3 times) the rate that D appears.
A. i only
B. ii only
C. i and ii
D. ii and iii
E. i and iii

Consider the reaction:
2 NO(g) + O2(g) →2 NO2(g)
If the instantaneous rate of reaction of nitric oxide (NO) is ‐ 0.016 M/s, at what rate is molecular oxygen reacting
A) ‐0.016 M/s
B) ‐0.032 M/s
C) ‐0.008 M/s
D) +0.016 M/s
E) +0.032 M/s

Given the following balanced equation, determine the rate of reaction with respect to [NOCl]. If the rate of Cl2 loss is 4.84 x 10-2 M/s, what is the rate of formation of NOCl?
2 NO(g) + Cl2(g) → 2 NOCl(g)
A) 4.84 x 10-2 M/s
B) 2.42 x 10-2 M/s
C) 1.45 x 10-1 M/s
D) 9.68 x 10-2 M/s
E) 1.61 x 10-2 M/s

Given the following balanced equation, determine the rate of reaction with respect to [SO2].
2 SO2 (g) + O2 (g) → 2 SO3 (g)
A. Rate = -1/2 Δ[SO2]/Δt
B. Rate = +1/2 Δ[SO2]/Δt
C. Rate = - Δ[SO2]/Δt
D. Rate = + 2Δ[SO2]/Δt
E. It is not possible to determine without more information.

The rate of decrease in N2H4 partial pressure in a closed reaction vessel is 75 torr/h. What is the rate of change of ammonia partial pressures and total pressure in vessel?
N2H4(g) + H2(g) → 2 NH3(g)
a) 75 torr, 300 torr
b) 150 torr, 300 torr
c) 150 torr, 150 torr
d) 150 torr, 0 torr
e) 75 torr, 0 torr

Consider this reaction.
4 NH3 (g) + 3 O2 (g) ⇌ 2 N2 (g) + 6 H2O (l)
If the rate formation of N2 is 0.10 M•s-1, what is the corresponding rate of dissapearance of O 2?
(A) 1.5 M•s-1
(B) 0.30 M•s-1
(C) 0.15 M•s-1
(D) 0.10 M•s-1

The balanced equation for the reaction of bromate ion with bromide in acidic solution is given by:
At a particular instant in time, the value of −Δ[Br -]/Δt is 2.0 x 10-3 mol/L s. What is the value of Δ[Br2]/Δt in the same units?
A. 1.2 x 10-3
B. 6.0 x 10-3
C. 3.3 x 10-3
D. 3.3 x 10-5
E. 2.0 x 10-3

For the reaction
BrO3- + 5Br - + 6H+ → 3Br2 + 3H2O
at particular time, -Δ[BrO3-]/ Δt = 1.5 x 10 -2 M/s.
What is -Δ [Br-]/ Δt at the same instant?
A) 13 M/s
B) 7.5 x 10-2 M/s
C) 1.5 x 10-2 M/s
D) 3.0 x 10-3 M/s
E) 330 M/s

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 = -(1/2)Δ [B]/ Δt
E) Δ[C]/ Δt = -(1/2)Δ [A]/ Δt

Using the format given in your text, which of the following rate equalities is correct for the following reaction?
4 NH3(g) + 7 O2 (g) → 4 NO2(g) + 6 H2O(g)

Consider the reaction N2(g) + 3H2(g) → 2NH3(g)
Suppose at a particular moment during the reaction molecular hydrogen is reacting at a rate of 0.084 M/s.
a. At what rate is ammonia being formed?
b. At what rate is molecular nitrogen reacting?
c. What is the average rate of the reaction?

Based on your knowledge of general rates answer the following question.

For the reaction,
4PH3(g) → P4(g) + 6H2(g)
the rate of reaction is 0.018 moles L−1s−1, what is the rate of formation of H 2?
a) 0.018 moles L−1s−1
b) 0.072 moles L−1s−1
c) 0.003 moles L−1s−1
d) 0.0045 moles L−1s−1
e) 0.108 moles L−1s−1

Under certain conditions, the average rate of appearance of oxygen gas in the reaction
2O3(g) → 3O2(g)
is 1.2 x 10–3 atm•s–1. What is the average rate, expressed in atm•s –1, for the disappearance of O3?
(A) 8.0 x 10–4
(B) 1.2 x 10–3
(C) 1.8 x 10–3
(D) 5.3 x 10–3

What is the balanced reaction for the following rate relationships?

Given the following balanced equation, if the rate of Cl2 loss is 4.24 × 10-2 M/s, what is the rate of formation of NOCl?

Which statement is true of the reaction below?
2 A (g) + B (g) → C (g) + 2 D (g)
a) B is lost at twice the rate that A is lost
b) D is gained at twice the rate that A is lost
c) A is lost at twice the rate that B is lost
d) C is gained at twice the rate that D is gained
e) The rate law must be known to answer this question

Consider the following chemical equation
12 HCIO4 (aq) + P4O10 (g) --> 4 H3PO4 (aq) + 6 Cl2O7 (g)
If the rate of the appearance with respect to H3PO4 is 5.72 x 10-5 M min-1, what is the rate of the appearance of Cl2O7?
A. 3.81 x 10-5 Mmin-1
B. 8.58 x 10-5 Mmin-1
C. 2.29 x 10-4 Mmin-1
D. 1.14 x 10-4 Mmin-1
E. 2.86 x 10-5 Mmin-1

For reaction
5 O2 (g) + 4 NH3 (g) → 4 NO (g) + 6 H2O (g)
if NH3 is being consumed at a rate of 0.50 M • s –1, at what rate is H2O being formed?
a) 0.33 M•s–1
b) 0.50 M•s–1
c) 0.75 M•s–1
d) 3.0 M•s–1

Is the
rate of disappearance of reactants always the same as the rate
of appearance of products?

You study the rate of a reaction, measuring both the concentration
of the reactant and the concentration of the product as
a function of time, and obtain the following results: Choose equivalent expressions for the rate of the reaction
in terms of the appearance or disappearance of the two
substances.

The isomerization of methyl isonitrile (CH3NC) to acetonitrile (CH3CN) was studied in the gas phase at 215 oC, and the following data were obtained:
Time (s)
[CH3NC]
(M)
0
0.0165
2000
0.0110
5000
0.00591
8000
0.00314
12000
0.00137
15000
0.00074
Calculate the average rate of disappearance of isonitrile, in M/s, for the time interval between each measurement.

The isomerization of methyl isonitrile (CH3NC) to acetonitrile (CH3CN) was studied in the gas phase at 215 oC, and the following data were obtained:
Time (s)
[CH3NC]
(M)
0
0.0165
2000
0.0110
5000
0.00591
8000
0.00314
12000
0.00137
15000
0.00074
Calculate
the average rate of reaction over the entire time of the
data from t = 0 to t = 15,000 s.

Consider the following hypothetical aqueous reaction: A(aq)B(aq). A flask is charged with 0.065 mol of A in a total volume of 100.0 mL. The following data are collected:
Time (min)
0
10
20
30
40
Moles of A
0.065
0.051
0.042
0.036
0.031
Calculate the number of moles of B at 10 min, assuming that there are no molecules of B at time zero.

What units are typically used to express the rate of a reaction?

Why is the reaction rate for reactants defined as the negative of the change in reactant concentration with respect to time, whereas for products it is defined as the change in reactant concentration with respect to time (with a positive sign)?

Consider the following reaction and data:H2 + 2ICl → 2HCl + I 2Time (s) I 2 concentration (M) 5 1.11 15 1.83a. What is the average rate of formation of I 2? Express your answer to three decimal places and include the appropriate units.b. Based on your answer to Part a, what is the average rate of formation of HCl? Express your answer to three decimal places and include the appropriate units.c. Based on your answer to Part a or b, what is the average rate of change of H 2? Remember that reactant concentrations decrease over time.Express your answer to three decimal places and include the appropriate units.

Consider the reaction:8H2S(g) + 4O2 → 8H2O(g) + S8(g)Δ[H2S]/Δt= - 0.019 M/sa. Find Δ[O2]/Δtb. Find Δ[H2O]/Δtc. Find Δ[S8]/Δtd. Find the rate of the reaction.

Consider the reaction: 8H2S(g) + 4O2(g) → 8H2O(g) + S8(g) Δ[H 2S]/Δt = -0.031 M/s a. Find Δ[O2]/Δt.b. Find Δ[H2O]/Δt.c. Find Δ[S8]/Δt.d. Find the rate of the reaction.

Consider the reaction
5Br−(aq) + BrO3−(aq) + 6H+(aq) → 3Br2(aq) + 3H2O(l)
The average rate of consumption of Br− is 2.06 × 10−4 M/s over the first two minutes. What is the average rate of formation of Br2 during the same time interval?
Express your answer with the appropriate units.

The decomposition of N2O5 can be described by the equation:
2N2O5 (soln) → 4NO2 (soln) + O 2 (g)
Given this data for the reaction at 45 degrees C in carbon tetrachloride solution, calculate the average rate for each successive time interval.
t(s) [N2O5] (M)
0 2.10
195 1.86
556 1.48
825 1.25
Interval: 0 s to 195 s
Reaction rate= _____M/s
195 s to 556 s
Reaction rate= _____M/s
556 s to 825 s
Reaction rate= _____M/s

Consider the reaction: 8H2S(g) + 4O2(g) → 8H2O(g) + S8(g) Δ[H2S]/Δt = -0.071 M/s a. Find Δ[O2]/Δt. Express your answer to two significant figures and include the appropriate units. b. Find Δ[H2O]/Δt. Express your answer to two significant figures and include the appropriate units. c. Find Δ[S8]/Δt. Express your answer to two significant figures and include the appropriate units. d. Find the rate of the reaction. Express your answer to two significant figures and include the appropriate units.

For the reaction,2NO(g) + 2H2(g) → N2(g) + 2H2O(g)at a particular time the concentration of NO was decreasing at an instantaneous rate of 0.54 moles L−1s-1. What is the rate of reaction?a) 0.54 moles L−1s-1b) 0.27 moles L−1s-1c) 2.16 moles L−1s-1d) 1.08 moles L−1s-1e) 0.135 moles L−1s-1

Complete the expressions for the rate of appearance of products and the rate of disappearance of reactants in each of the following reactions. NOTE: add only minus signs and fractions where appropriate.
a) Cl2O2(g) → 2ClO(g)
b) N2O5(g) → NO2(g) + NO3(g)

Consider the reaction:
2H3PO4 → P2O5 + 3H2O
Using the information in the following table,
Time (s) P 2O5 (M)
0 0
10 1.30 x 10 -3
20 4.30 x 10 -3
30 6.10 x 10 -3
40 7.30 x 10 -3
50 7.90 x 10 -3
i) Calculate the average rate of formation of P2O5 between 10.0 and 40.0 s.
ii) Rate of formation of P2O5 = 2.00 x 10-4 M/ s. What is the average rate of decomposition of H3PO4 between 10.0 and 40.0 s?

Consider the following reaction: NO2(g) → NO(g) + 1/2 O2(g). The following data were collected for the concentration of NO2 as a function of time. Express your answer using two significant figures.a. What is the average rate of the reaction between 10 and 20?b. What is the average rate of the reaction between 50 and 60 ?c. What is the rate of formation of NO2 between 50 and 60 ?

In the Haber process for the production of ammonia,N2 (g) + 3H2 (g) + 2NH3 (g) what is the relationship between the rate of production of ammonia and the rate of consumption of hydrogen?

Consider the general reaction aA + bB → cC and the following average rate data over some time period Δt:Determine a set of possible coefficients to balance this general reaction.

What are the units for each of the following if the concentrations are expressed in moles per liter and the time in seconds? a. rate of a chemical reaction

You may want to reference (Pages 571 - 575)Section 14.2 while completing this problem.A flask is charged with 0.100 mol of A and allowed to react to form B according to the hypothetical gas-phase reaction A(g) → B(g). The following data are collected:Which of the following would be needed to calculate the rate in units of concentration per time: (i) the pressure of the gas at each time, (ii) the volume of the reaction flask, (iii) the temperature, or (iv) the molecular weight of A?

Reaction rate is expressed in terms of changes in concentration of reactants and products. Write a balanced equation for the reaction with this rate expression:

Reaction rate is expressed in terms of changes in concentration of reactants and products. Write a balanced equation for the reaction with this rate expression:

The formation of ammonia is one of the most important processes in the chemical industry:N2(g) + 3H2(g) ⟶2NH3(g)Express the rate in terms of changes in [N2], [H2], and [NH3].

Although the depletion of stratospheric ozone threatens life on Earth today, its accumulation was one of the crucial processes that allowed life to develop in prehistoric times:3O2(g) ⟶2O3(g)(a) Express the reaction rate in terms of [O2] and [O3].

Write the general rate equation for the following reaction, as written, for each of the components
C2H6(I) +7/2O2(g) → 2CO2(q) + 3H2O(I)

For each of the following gas-phase reactions, indicate how the rate of disappearance of each reactant is related to the rate of appearance of each product.H2O2(g) → H2(g) + O2(g)

Ozone decomposes to oxygen according to the equation 2O3 (g) ⟶ 3 O2 (g). Write the equation that relates the rate expressions for this reaction in terms of the disappearance of O3 and the formation of oxygen.

For each of the following gas-phase reactions, indicate how the rate of disappearance of each reactant is related to the rate of appearance of each product.2 N2O(g) → 2 N2(g) + O2(g)

In the nuclear industry, chlorine trifluoride is used to prepare uranium hexafluoride, a volatile compound of uranium used in the separation of uranium isotopes. Chlorine trifluoride is prepared by the reactionCl2 (g) + 3 F2 (g) ⟶ 2 ClF3 (g).Write the equation that relates the rate expressions for this reaction in terms of the disappearance of Cl2 and F2 and the formation of ClF3.

For each of the following gas-phase reactions, indicate how the rate of disappearance of each reactant is related to the rate of appearance of each product.N2(g) + 3 H2(g) → 2 NH3(g)

For each of the following gas-phase reactions, indicate how the rate of disappearance of each reactant is related to the rate of appearance of each product.C2H5NH2(g) → C2H4(g) + NH3(g)

You may want to reference (Pages 571 - 575) Section 14.2 while completing this problem.For each of the following gas-phase reactions, write the rate expression in terms of the appearance of each product and disappearance of each reactant:2 SO2(g) + O2(g) → 2 SO3(g)

You may want to reference (Pages 571 - 575) Section 14.2 while completing this problem.For each of the following gas-phase reactions, write the rate expression in terms of the appearance of each product and disappearance of each reactant:2 NO(g) + 2 H2(g) → N2(g) + 2 H2O(g)

You may want to reference (Pages 571 - 575) Section 14.2 while completing this problem.For each of the following gas-phase reactions, write the rate expression in terms of the appearance of each product and disappearance of each reactant:2 H2O(g) → 2 H2(g) + O2(g)N2(g) + 2 H2(g) → N2H4(g)

Consider the following reaction: 2 N2O(g) → 2 N2(g) + O2(g). Express the rate of the reaction in terms of the change in concentration of each of the reactants and products.

Consider the following reaction: 2 HBr(g) → H2(g) + Br2(g)Express the rate of the reaction in terms of the change in concentration of each of the reactants and products.

Consider the reaction: 2 A(g) + B(g) → 3 C(g). Determine the expression for the rate of the reaction with respect to each of the reactants and products.

Consider the reaction A(g) + 1/2 B(g) → 2 C(g). large{ m A(g) + frac{_1}{^2}B(g) ightarrow 2C(g)}Identify the expression for the rate of the reaction with respect to each of the reactants and products.

Consider the gas-phase reaction between nitric oxide and bromine at 273 oC2NO(g) + Br2(g) → 2NOBr(g).The following data for the initial rate of appearance of NOBr were obtained:Experiment [NO] [Br2](M)Initial Rate of Appearance of NOBr (M/s) 10.100.202420.250.2015030.100.506040.350.50735How is the rate of appearance of NOBr related to the rate of disappearance of Br2?

At 40°C, H2O2(aq) will decompose according to the following reaction:2H2O2 (aq) → 2H2O (l) + O2 (g)The following data were collected for the concentration of H 2O2 at various times.b. What are these rates for the time period 2.16 x 10 4 s to 4.32 x 104 s?

An average reaction rate is calculated as the change in the concentration of reactants or products over a period of time in the course of the reaction. An instantaneous reaction rate is the rate at a particular moment in the reaction and is usually determined graphically.
The reaction of compound A forming compound B was studied and the following data were collected:
Time (s) [A] (M)
0. 0.184
200. 0.129
500. 0.069
800. 0.031
1200. 0.019
1500. 0.016
a. What is the average reaction rate between 0 s and 1500 s?
b. What is the average reaction rate between 500 s and 1200 s?
c. What is the instantaneous rate of the reaction at t = 800 s?

Consider the reaction 4PH3 (g) → P4 (g) + 6H2 (g) If, in a certain experiment, over a specific time period, 0.0048 mole of PH 3 is consumed in a 2.0‑L container each second of reaction, what are the rates of production of P4 and H2 in this experiment?

At 40°C, H2O2(aq) will decompose according to the following reaction:2H2O2 (aq) → 2H2O (l) + O2 (g)The following data were collected for the concentration of H 2O2 at various times.a. Calculate the average rate of decomposition of H 2O2 between 0 and 2.16 x 104 s. Use this rate to calculate the average rate of production of O2(g) over the same time period.

You may want to reference (Pages 571 - 575)Section 14.2 while completing this problem.A flask is charged with 0.100 mol of A and allowed to react to form B according to the hypothetical gas-phase reaction A(g) → B(g). The following data are collected:Calculate the average rate of disappearance of A between t = 0 s and t = 40 s, in units of mol/s.

You may want to reference (Pages 571 - 575)Section 14.2 while completing this problem.A flask is charged with 0.100 mol of A and allowed to react to form B according to the hypothetical gas-phase reaction A(g) → B(g). The following data are collected:Calculate the average rate of disappearance of A between t = 40 s and t = 80 s, in units of mol/s.

You may want to reference (Pages 571 - 575)Section 14.2 while completing this problem.A flask is charged with 0.100 mol of A and allowed to react to form B according to the hypothetical gas-phase reaction A(g) → B(g). The following data are collected:Calculate the average rate of disappearance of A between t = 80 s and t = 120 s, in units of mol/s.

You may want to reference (Pages 571 - 575)Section 14.2 while completing this problem.A flask is charged with 0.100 mol of A and allowed to react to form B according to the hypothetical gas-phase reaction A(g) → B(g). The following data are collected:Calculate the average rate of disappearance of A between t = 120 s and t = 160 s, in units of mol/s.

The isomerization of methyl isonitrile (CH3NC) to acetonitrile (CH3CN) was studied in the gas phase at 215˚C, and the following data were obtained:Which is greater, the average rate between t = 2000 and t = 12,000 s, or between t = 8000 and t = 15,000 s?

You may want to reference (Pages 571 - 575) Section 14.2 while completing this problem.The rate of disappearance of HCl was measured for the following reaction: CH3OH(aq) + HCl(aq) CH3Cl(aq) + H2O(l). The following data were collected:Calculate the average rate of reaction, in M/s, for the time interval between each measurement.

You may want to reference (Pages 571 - 575) Section 14.2 while completing this problem.The rate of disappearance of HCl was measured for the following reaction: CH3OH(aq) + HCl(aq) CH3Cl(aq) + H2O(l). The following data were collected:Calculate the average rate of reaction for the entire time for the data from t = 0.0 min to t = 430.0 min.

The rate of disappearance of HCl was measured for the following reaction:CH3OH(aq) + HCl(aq) CH3Cl(aq) + H2O(l)The following data were collected: Time (min) [HCl] (M) 0.01.8553.01.58107.01.36215.01.02431.00.580Calculate the average rate of reaction for the entire time for the data from t = 0.0 min to t = 431.0 min.

You may want to reference (Pages 571 - 575) Section 14.2 while completing this problem.The rate of disappearance of HCl was measured for the following reaction: CH3OH(aq) + HCl(aq) CH3Cl(aq) + H2O(l). The following data were collected:Which is greater, the average rate between t = 54.0 and t = 215.0 min, or between t = 107.0 and t = 430.0 min?

If the experiment below is run for 60 s, 0.16 mol A remain. Which of the following statements is or are true?After 60 s there are 0.84 mol B in the flask.The decrease in the number of moles of A from t1 = 0 to t2 = 20 s is greater than that for t1 = 40 to t2 = 60 s.The average rate for the reaction from t1 = 40 to t2 = 60 s is 7.0 10-3 M/s.

The compound AX2 decomposes according to the equation 2AX2(g) → 2AX(g) + X2(g). In one experiment, [AX2] was measured at various times and these data were obtained:(a) Find the average rate over the entire experiment.

(a) Use the data below to calculate the average rate from 8.0 to 20.0 s.

Suppose that for the reaction K + L → M, you monitor the production of M over time, and then plot the followinggraph from your data:Is the reaction occurring at a constant rate from t = 0 to t = 15 min?

Suppose that for the reaction K + L → M, you monitor the production of M over time, and then plot the followinggraph from your data:Is the reaction completed at t = 15 min?

Suppose that for the reaction K + L → M, you monitor the production of M over time, and then plot the followinggraph from your data:Suppose the reaction as plotted here were started with 0.20 mol K and 0.40 mol L. After 30 min, an additional 0.20 mol K are added to the reaction mixture. Which of the following correctly describes how the plot would look from t = 30 min to t = 60 min?(i) [M] would remain at the same constant value it has at t = 30 min.(ii) [M] would increase with the same slope as t = 0 to 15 min, until t = 45 min at which point the plot becomes horizontal again.(iii) [M] decreases and reaches 0 at t = 45 min.

The decomposition of NOBr is studied manometrically because the number of moles of gas changes; it cannot be studied colorimetrically because both NOBr and Br2 are reddish brown:2NOBr(g) ⟶2NO(g) + Br2(g)Use the data below to answer the following:(a) Determine the average rate over the entire experiment.

In a clock reaction, a dramatic color change occurs at a time determined by concentration and temperature. Consider the iodine clock reaction, whose overall equation is2 I−(aq) + S 2O82−(aq) ⟶ I 2(aq) + 2 SO42−(aq)Once the S 2O32− is consumed, the excess I 2 forms a blue-black product with starch present in solution:I2 + starch ⟶ starch•I2 (blue-black)The rate of the reaction is also influenced by the total concentration of ions, so KCl and (NH 4)2SO4 are added to maintain a constant value. Use the data below, obtained at 23˚C, to determine the average rate for each trial.

The decomposition of NOBr is studied manometrically because the number of moles of gas changes; it cannot be studied colorimetrically because both NOBr and Br2 are reddish brown:2NOBr(g) ⟶2NO(g) + Br2(g)Use the data below to answer the following:(b) Determine the average rate between 2.00 and 4.00 s.

This graph shows the concentration of the reactant A in the reaction A.Determine the average rate of the reaction between 0 and 10 seconds.

Consider the following hypothetical aqueous reaction: A(aq) → B(aq). A flask is charged with 0.065 mol of A in a total volume of 100.0 mL. The following data are collected:Time (min)010203040Moles of A0.0650.0510.0420.0360.031Calculate the average rate of disappearance of A between t = 0 min and t = 10 min, in units of M/s.

Consider the following hypothetical aqueous reaction: A(aq) → B(aq). A flask is charged with 0.065 mol of A in a total volume of 100.0 mL. The following data are collected:Time (min)010203040Moles of A0.0650.0510.0420.0360.031Between t = 10 min and t = 30 min, what is the average rate of appearance of B in units of M/s? Assume that the volume of the solution is constant.

Consider the following hypothetical aqueous reaction: A(aq) → B(aq). A flask is charged with 0.065 mol of A in a total volume of 100.0 mL. The following data are collected:Time (min)010203040Moles of A0.0650.0510.0420.0360.031Calculate the number of moles of B at 20 min, assuming that there are no molecules of B at time zero and that A cleanly converts to B with no intermediates.

Consider the following hypothetical aqueous reaction: A(aq) → B(aq). A flask is charged with 0.065 mol of A in a total volume of 100.0 mL. The following data are collected:Time (min)010203040Moles of A0.0650.0510.0420.0360.031Calculate the number of moles of B at 30 min, assuming that there are no molecules of B at time zero and that A cleanly converts to B with no intermediates.

Consider the following hypothetical aqueous reaction: A(aq) → B(aq). A flask is charged with 0.065 mol of A in a total volume of 100.0 mL. The following data are collected:Time (min)010203040Moles of A0.0650.0510.0420.0360.031Calculate the number of moles of B at 40 min, assuming that there are no molecules of B at time zero and that A cleanly converts to B with no intermediates.

Consider the following hypothetical aqueous reaction: A(aq) → B(aq). A flask is charged with 0.065 mol of A in a total volume of 100.0 mL. The following data are collected:Time (min)010203040Moles of A0.0650.0510.0420.0360.031Calculate the average rate of disappearance of A between t = 10 min and t = 20 min, in units of M/s.

Consider the following hypothetical aqueous reaction: A(aq) → B(aq). A flask is charged with 0.065 mol of A in a total volume of 100.0 mL. The following data are collected:Time (min)010203040Moles of A0.0650.0510.0420.0360.031Calculate the average rate of disappearance of A between t = 20 min and t = 30 min, in units of M/s.

Consider the following hypothetical aqueous reaction: A(aq) → B(aq). A flask is charged with 0.065 mol of A in a total volume of 100.0 mL. The following data are collected:Time (min)010203040Moles of A0.0650.0510.0420.0360.031Calculate the average rate of disappearance of A between t = 30 min and t = 40 min, in units of M/s.

A study of the rate of dimerization of C4H6 gave the data shown in the table: 2 C4H6 ⟶ C8H12(a) Determine the average rate of dimerization between 0 s and 1600 s, and between 1600 s and 3200 s.

A study of the rate of the reaction represented as 2A ⟶ B gave the following data:(a) Determine the average rate of disappearance of A between 0.0 s and 10.0 s, and between 10.0 s and 20.0 s.

Consider the following reaction: 2 N2O(g) → 2 N2(g) + O2(g). In the first 13.0 s of the reaction, 1.8 × 10−2 mol of O2 is produced in a reaction vessel with a volume of 0.380 L. What is the average rate of the reaction over this time interval?

You may want to reference(Pages 571 - 575)Section 14.2 while completing this problem.Consider the combustion of ethylene: C2H4(g) + 3 O2(g) → 2 CO2(g) + 2 H2O(g). If the concentration of C2H4 is decreasing at the rate of 3.7×10−2 M/s, what is the rate of change in the concentration of H2O?

Consider the following reaction: 2 N2O(g) → 2 N2(g) + O2(g). In the first 15.0 s of the reaction, 0.015 mol of O2 is produced in a reaction vessel with a volume of 0.500 L. Predict the rate of change in the concentration of N2O over this time interval. In other words, what is Δ[N2O]/Δt?large{frac {Delta [
m N_2O]}{Delta t}}

You may want to reference(Pages 571 - 575)Section 14.2 while completing this problem.Consider the following reaction: N2H4(g) + H2(g) → 2NH3(g). If the rate of decrease for the partial pressure of N2H4 in a closed reaction vessel is 76 torr/h, what is the rate of change of total pressure in the vessel during the reaction?

Consider the following reaction: NO2(g) → NO(g) + 1/2 O2(g). The following data were collected for the concentration of NO2 as a function of time: Time (s) [NO2]
(M) 01.000100.951200.904300.860400.818500.778600.740700.704800.670900.6371000.606What is the average rate of the reaction between 10 and 20 s?

Consider the following reaction: NO2(g) → NO(g) + 1/2 O2(g). The following data were collected for the concentration of NO2 as a function of time: Time (s) [NO2] (M) 01.000100.951200.904300.860400.818500.778600.740700.704800.670900.6371000.606What is the rate of formation of O2 between 50 and 60 s?

Consider the following reaction: NO2(g) → NO(g) + 1/2 O2(g). The following data were collected for the concentration of NO2 as a function of time: Time (s) [NO2] (M) 01.000100.951200.904300.860400.818500.778600.740700.704800.670900.6371000.606What is the average rate of the reaction between 50 and 60 s?

You may want to reference (Pages 625 - 628) Section 14.2 while completing this problem.Consider the balanced chemical equation: H2O2(aq) + 3I–(aq) + 2H+(aq) → I3–(aq) + 2H2O(l)In the first 13.0 s of the reaction, the concentration of I– drops from 1.000 M to 0.811 M. Predict the rate of change in the concentration of I3–(Δ[I3–]/Δt).

Consider the following reaction: 2 HBr(g) → H2(g) + Br2(g)In the first 23.0 s of this reaction, the concentration of HBr dropped from 0.570 M to 0.482 M. Calculate the average rate of the reaction in this time interval.

Consider the following reaction: 2 HBr(g) → H2(g) + Br2(g)The volume of the reaction vessel was 1.50 L. What amount of Br2 (in moles) was formed during the first 15.0 s of the reaction if the concentration of HBr dropped from 0.600 M to 0.512 M?

Consider the following reaction: C4H8(g) → 2 C2H4(g). The following data were collected for the concentration of C4H8 as a function of time: Time (s) [C4H8]
(M) 01.000100.913200.835300.763400.697500.637What is the average rate of the reaction between 0 and 10 s?

Consider the following reaction: C4H8(g) → 2 C2H4(g). The following data were collected for the concentration of C4H8 as a function of time: Time (s) [C4H8] (M) 01.000100.913200.835300.763400.697500.637What is the rate of formation of C2H4 between 20 and 30 s?

Consider the following reaction: C4H8(g) → 2 C2H4(g). The following data were collected for the concentration of C4H8 as a function of time: Time (s) [C4H8] (M) 01.000100.913200.835300.763400.697500.637What is the average rate of the reaction between 40 and 50 s?

Consider the following reaction: H2(g) + Br2(g) → 2HBr. The graph below shows the concentration of Br2 as a function of time.Use the graph to calculate the average rate of the reaction between 0 and 25 s.

Consider the following reaction: 2 H2O2(aq) → 2 H2O(l) + O2(g). The graph shows the concentration of H2O2 as a function of time. Use the graph to calculate the following.The average rate of the reaction between 10 and 20 s.

Consider the following reaction: 2 H2O2(aq) → 2 H2O(l) + O2(g). The graph shows the concentration of H2O2 as a function of time. Use the graph to calculate the following.If the initial volume of the H2O2 solution is 1.6 L, what total amount of O2 (in moles) is formed in the first 50 s of reaction?

The aqueous reaction of KOH with HBr is:
KOH(aq) + HBr(aq) → KBr(aq) + H2O(l)
At the start of such a reaction, the concentration of KOH(aq) is 0.275M. After 3.05 seconds the concentration is observed to be 0.0557M KOH(aq).
What is the rate of the reaction?

You may want to reference (Pages 571 - 575)Section 14.2 while completing this problem.A flask is charged with 0.100 mol of A and allowed to react to form B according to the hypothetical gas-phase reaction A(g) → B(g). The following data are collected:Calculate the number of moles of B at t = 40 s, assuming that A is cleanly converted to B with no intermediates.

You may want to reference (Pages 571 - 575)Section 14.2 while completing this problem.A flask is charged with 0.100 mol of A and allowed to react to form B according to the hypothetical gas-phase reaction A(g) → B(g). The following data are collected:Calculate the number of moles of B at t = 80 s, assuming that A is cleanly converted to B with no intermediates.

You may want to reference (Pages 571 - 575)Section 14.2 while completing this problem.A flask is charged with 0.100 mol of A and allowed to react to form B according to the hypothetical gas-phase reaction A(g) → B(g). The following data are collected:Calculate the number of moles of B at t = 120 s, assuming that A is cleanly converted to B with no intermediates.

You may want to reference (Pages 571 - 575)Section 14.2 while completing this problem.A flask is charged with 0.100 mol of A and allowed to react to form B according to the hypothetical gas-phase reaction A(g) → B(g). The following data are collected:Calculate the number of moles of B at t = 160 s, assuming that A is cleanly converted to B with no intermediates.

Express the rate of this reaction in terms of the change in concentration of each of the reactants and products:2A(g) ⟶B(g) + C(g)When [C] is increasing at 2 mol/L•s, how fast is [A] decreasing?

Express the rate of this reaction in terms of the change in concentration of each of the reactants and products:D(g) ⟶ 3/2 E(g) + 5/2F(g)When [E] is increasing at 0.25 mol/L•s, how fast is [F] increasing?

Express the rate of this reaction in terms of the change in concentration of each of the reactants and products:A(g) + 2B(g) ⟶ C(g)When [B] is decreasing at 0.5 mol/L•s, how fast is [A] decreasing?

Express the rate of this reaction in terms of the change in concentration of each of the reactants and products:2D(g) + 3E(g) + F(g) ⟶ 2G(g) + H(g)When [D] is decreasing at 0.1 mol/L•s, how fast is [H] increasing?

Although the depletion of stratospheric ozone threatens life on Earth today, its accumulation was one of the crucial processes that allowed life to develop in prehistoric times:3O2(g) ⟶2O3(g)(b) At a given instant, the reaction rate in terms of [O2] is 2.17 x 10-5 mol/L•s. What is it in terms of [O3]?

Experiments during a recent summer on a number of fireflies (small beetles, Lampyridaes photinus) showed that the average interval between flashes of individual insects was 16.3 s at 21.0°C and 13.0 s at 27.8°C.b. What would be the average interval between flashes of an individual firefly at 30.0°C?

Experiments during a recent summer on a number of fireflies (small beetles, Lampyridaes photinus) showed that the average interval between flashes of individual insects was 16.3 s at 21.0°C and 13.0 s at 27.8°C.a. What is the apparent activation energy of the reaction that controls the flashing?b. What would be the average interval between flashes of an individual firefly at 30.0°C?c. Compare the observed intervals and the one you calculated in part b to the rule of thumb that the Celsius temperature is 54 minus twice the interval between flashes.

The reaction 2NO(g) + O2 (g) → 2NO2 (g) is second order in NO and first order in O2. When [NO]= 4.1×10−2 M and [O2]= 3.6×10−2 M , the observed rate of disappearance of NO is 9.3×10−5 M/s .What is the rate of disappearance of O2 at this moment?

Dinitrogen monoxide decomposes into nitrogen and oxygen when heated. The initial rate of the reaction is 2.4 × 10−2 M/s. What is the initial rate of change of the concentration of N2O (that is, Δ[N2O]/Δt)?2 N2O(g) → 2 N2(g) + O2(g)

Consider the following reaction in aqueous solution:5 Br−(aq) + BrO3 −(aq) + 6 H+(aq) ⟶ 3 Br2 (aq) + 3 H2O(l)If the rate of disappearance of Br– (aq) at a particular moment during the reaction is 3.5 × 10−4 M s−1, what is the rate of appearance of Br2(aq) at that moment?

Consider the combustion of H2(g): 2 H2(g) + O2(g) → 2 H2O(g). If hydrogen is burning at the rate of 0.50 mol/s, what is the rate of consumption of oxygen?

The reaction 2 NO(g) + Cl2(g) → 2 NOCl(g) is carried out in a closed vessel. If the partial pressure of NO is decreasing at the rate of 56 torr/min, what is the rate of change of the total pressure of the vessel?

Consider the combustion of H2(g): 2 H2(g) + O2(g) → 2 H2O(g). If hydrogen is burning at the rate of 0.50 mol/s, what is the rate of formation of water vapor?

You may want to reference(Pages 571 - 575)Section 14.2 while completing this problem.Consider the combustion of ethylene: C2H4(g) + 3 O2(g) → 2 CO2(g) + 2 H2O(g). If the concentration of C2H4 is decreasing at the rate of 3.7×10−2 M/s, what is the rate of change in the concentration of CO2?

You may want to reference(Pages 571 - 575)Section 14.2 while completing this problem.Consider the following reaction: N2H4(g) + H2(g) → 2NH3(g). If the rate of decrease for the partial pressure of N2H4 in a closed reaction vessel is 76 torr/h, what is the rate of change for the partial pressure of NH3 in the same vessel?

For the reaction A + 2B → C under a given set of conditions, the initial rate is 0.100 M/s. What is Δ[B]/Δt under the same conditions?

You may want to reference (Pages 625 - 628) Section 14.2 while completing this problem.Consider the balanced chemical equation: H2O2(aq) + 3I–(aq) + 2H+(aq) → I3–(aq) + 2H2O(l)In the first 13.0 s of the reaction, the concentration of I– drops from 1.000 M to 0.811 M. Predict the rate of change in the concentration of H2O2(Δ[H2O2]/Δt).

Consider the reaction: 2 A(g) + B(g) → 3 C(g). When A is changing at a rate of -0.140 M s-1, how fast is B changing?

Consider the reaction: 2 A(g) + B(g) → 3 C(g). When A is decreasing at a rate of 0.100 M/s, how fast is C increasing?

Consider the reaction A(g) + 1/2 B(g) → 2 C(g). When C is increasing at a rate of 3.0×10−2 M s-1 , how fast is B decreasing?

Consider the reaction A(g) + 1/2 B(g) → 2 C(g). When C is increasing at a rate of 3.0×10−2 M s-1 , how fast is A decreasing?

Consider the reaction: Cl2(g) + 3F2(g) → 2ClF3(g).Given that Δ[Cl2]/Δt = -0.054 M/s. Find Δ[F2]/Δt

Consider the reaction: Cl2(g) + 3F2(g) → 2ClF3(g).Given that Δ[Cl2]/t = -0.054 M/s. Find Δ[ClF3]/Δt

Consider the reaction: Cl2(g) + 3F2(g) → 2ClF3(g).Given that Δ[Cl2]/Δt = -0.054 M/s. Find the rate of the reaction.

Consider the reaction: 8 H2S(g) + 4 O2(g) → 8 H2O(g) + S8(g)Given that Δ[H2S]/Δt = -0.049 M/s. Find Δ[O2]/Δt.

Consider the reaction: 8 H2S(g) + 4 O2(g) → 8 H2O(g) + S8(g)Given that Δ[H2S]/Δt = -0.049 M/s. Find Δ[H2O]/Δt.

Consider the reaction: 8 H2S(g) + 4 O2(g) → 8 H2O(g) + S8(g)Given that Δ[H2S]/Δt = -0.049 M/s. Find Δ[S8]/Δt.

Consider the reaction: 8 H2S(g) + 4 O2(g) → 8 H2O(g) + S8(g)Given that Δ[H2S]/Δt = -0.049 M/s. Find the rate of the reaction.

Consider the following reaction: H2(g) + Br2(g) → 2HBr. The graph below shows the concentration of Br2 as a function of time.Make a rough sketch of a curve representing the concentration of HBr as a function of time. Assume that the initial concentration of HBr is zero.

The thiosulfate ion (S2O32-) is oxidized by iodine as follows:2S2O32- (aq) + I2 (aq) → S4O62- (aq) + 2I - (aq)In a certain experiment, 7.05 x 10-3 mol/L of S2O32- is consumed in the first 11.0 seconds of the reaction. Calculate the rate of consumption of S2O32-. Calculate the rate of production of iodide ion.

At a given temperature, the elementary reaction A ⇌ B in the forward direction is first order in A with a rate constant of 4.30 x 102 s-1. The reverse reaction is first order in B and the rate constant is 5.70 x 102 s-1.What is the value of the equilibrium constant for the reaction A ⇌ B at this temperature? What is the value of the equilibrium constant for the reaction B ⇌ A at this temperature?

Consider the following reaction: 2HBr (g) → H2 (g) + Br2 (g) Part B In the first 23.0 s of this reaction the of HBr dropped from 0.550 M to 0.457 M. Calculated the average rate of the reaction in this time interval. Express your answer using two significant figures. Part CIf the volume of the reaction in part (b) was 1.50 L. what amount of Br2 (in moles) was formed during the 15.0 is of the reaction?Express your answer using two significant figures.

In the reaction 2N2O5 → 4NO2 + O2 given that the rate law is v = k[N 2O5] where v is the reaction rate or reaction velocity, calculate the rate of formation of NO 2 if the instantaneous rate of reaction is 1.7 x 10-6 mol L-1 s-1.

The decomposition of N2O5 can be described by the equation2N2O5 (soln) → 4NO2 (soln) + O2 (g)Given these data for the reaction at 45° C in carbon tetrachloride solution, calculate the average rate of reaction for each successive time interval.

a. If Δ[NO3] / Δt is -21.51 x 104 mM/min in the following reaction, what is the rate of appearance of NO2? NO3(g) + NO(g) → 2NO(g) b. What is the rate of change in [NO2] in the following reaction if Δ[NO3] / Δt is -23.36 x 10-1 mM/min? 2N3(g) → 2NO2(g) + O2(g)

The rate of the following reaction is 0.720 M/s. What is the relative rate of each species in the reaction?

A reaction generates chlorine gas (Cl 2) as a product. The reactants are mixed and sealed in a 500.-mL container. After 30.0 minutes, 2.05 x 10-3 mol of Cl2 has been generated. Calculate the average rate of the reaction.

In a study of the decomposition of nitrosyl bromide at 10°C.NOBr → NO + 1/2 Br2 the following data were obtained: (1) The observed half life for this reaction when the starting concentration is 0.311 M is _________ s and when the starting concentration is 0.156 M is ________s. (2) The average Δ(1/[NOBr])/Δt from t = 0 s to t = 5.00 s is __________ M-1 s-1. The average Δ(1/[NOBr])/Δt from t = 5.00 s to t = 15.0 s is ___________M-1 s-1.

The following chemical reaction was performed and the concentration of CCl4 was measured over time. Cl2 (g) + CHCl3 (g) → HCl (g) + CCI (g) The [CCl4] after 9 s was 0.153 mo/L. After 138 s, the [CCl4] was 0.374 mol/L. Calculate the rate of reaction.

The decomposition of dinitrogen pentoxide is described by the chemical equation 2N2O5(g) → 4NO2(g) + O2(g) If the rate of appearance of NO 2 is equal to 0.78 mol/min at a particular moment, what is the rate of appearance of O2 at that moment?

For the gas phase decomposition of dimethyl ether at 500°C, the rate of the reaction is determined by measuring the appearance of CH4. CH3OCH3 → CH4 + H2 + CO At the beginning of the reaction, the concentration of CH 4 is 0 M. After 26.3 min the concentration has increased to 4.53 x 10-2 M. What is the rate of the reaction?

The following chemical reaction was performed and the concentration of HCl was measured over time. Cl2 (g) + CHCl3 (g) → HCl (g) + CCl4 (g) The [HCI] after 15 s was 0.184 mol/L. After 138 s, the [HCI] was 0.451 mollL. Calculate the rate of reaction.

Suppose a small lake is contaminated with an insecticide that decomposes with time. An analysis done in June shows the decomposition product concentration to be 3.13 x 10-4 mol/L. An analysis done 35 days later shows the concentration of decomposition product to be 7.33 x 10-4 mol/L. Assume the lake volume remains constant and calculate the average rate of decomposition of the insecticide.

Consider the decomposition of dinitrogen pentoxide: 2 N2O5 (g) → 4 NO2 (g) + O2 (g) The following data were collected for the reaction at a given temperature: What is the average rate of formation of NO2 after 4 seconds of reaction? Be sure to include a minus sign if your calculated result is negative. Your answer should be expressed in units of M/s and with the correct number of significant digits, but do not include the units in your submitted answer.

Consider the reaction 8H2S(g) + 4O2 (g) → 8H2O(g) + S8 (g) Δ[H2S]/Δt = -0.031 M/s Part AFind Δ[O2]/Δt. Express your to two significant figure and include the appropriate units. Part BFind Δ[H2O]/Δt. Express your answer to two significant figures and include the appropriate units. Part CFind Δ[S8]/Δt. Express your answer to two significant figure and include the appropriate units. Part D Find the rate of the reaction. Express your answer to two significant figure and include the appropriate units.

Consider the reaction, 2NH3 (g) → N2 (g) + 3H2( g) If the rate of hydrogen production is 0.030 mol L-1 s-1, then the rate of nitrogen production is a. 0.030 mol L-1 s-1b. 0.010 mol L-1 s-1c. 0.020 mol L-1 s-1d. 0.090 mol L-1 s-1

The decomposition of N2O5 can be described by the equation2N2O5 → 4NO2 + O2Given these data for the reaction at 45 °C in carbon tetrachloride solution, calculate the average rate of reaction for each successive time interval.t(s) [N2O5]0 2.04135 1.87536 1.46795 1.24i) Reaction rate from 0-135 is ?ii) Reaction rate from 135-536 is ?iii) Reaction rate from 536-795 is ?

The decomposition of N2O5 can be described by the equation.2N2O5 (soln) → 4NO2 (soln) + O2 (g)Given this data for the reaction at 45°C in carbon tetrachloride solution, calculate the average rate for each successive time interval.t(s) [N2O5] (M)0 2.10195 1.86556 1.48825 1.25i) Interval: 0 s to 195 sReaction rate= _____M/sii) Interval: 195 s to 556 sReaction rate= _____M/siii) Interval: 556 s to 825 sReaction rate= _____M/s