# The first-order rate constant for photodissociation of A is 5.97 1/h. Calculate the time needed for the concentration of A to decrease to the following quantities. a. 5% of its original value h b. one-third of its initial concentration h

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1. ## chemistry

The first-order rate constant for photodissociation of A is 5.97 1/h. Calculate the time needed for the concentration of A to decrease to the following quantities. a. 5% of its original value h b. one-third of its initial concentration h
2. ## Chemistry Lab

*The decomposition of acetaldehyde is a first order reaction with a specific rate constant of 6.0 X 10^-1 / min. CH₃CHO --> CH₄ + CO 1. Calculate the initial rate when the concentration of acetaldehyde is 0.80M. 2. Calculate the time needed for the
3. ## Chemistry

The half-life for the second-order reaction of a substance A is 55.8 s when concentration of initial A = 0.69 M. Calculate the time needed for the concentration of A to decrease to the following values. (a) 1/8 of its original value (b) 1/9 of its original
4. ## Science work

A reaction is thought to be second order with respect to the concentration of carbon monoxide. What evidence would support this? Answer options... A. Changing the initial concentration would have no effect on the rate. B. Any change in the initial
5. ## Chemistry

What would be the concentration of dinitrogen pentoxide after 6.00 X 10(2) seconds and how long would it take for the concentration of N2O2 to decrease to 10.0% of its initial value in the following equation... N2O5 to NO2 and O2 initial concentration is
6. ## Chemistry

I know how to find half-lives, but I have trouble finding the length of time it would take for the concrentration of X to decrease to Y% of its initial value. For example, this is one of the problems: Methyl isocyanide, CH3NC, isomerizes when heated to
7. ## Chemistry

The half-life for the second-order reaction of a substance A is 58.2 s when A0 = 0.63 mol L-1 Calculate the time needed for the concentration of A to decrease to the following values. (a) one-third of its original value (b) one-sixth of its original value
8. ## Chemistry

I'm supposed to calculate the rate equation, including k, for the reaction whose data is given in the table: Experiment: 1 2 3 Initial Concentration X: 0.10, 0.10, 0.60 Initial Concentration Y: 0.20, 0.10, 0.10 Measured Initial Rate: 2.57, 1.25, 1.27 (I
9. ## chemistry

What would be the concentration of dinitrogen pentoxide after 6.00 X 10(2) seconds and how long would it take for the concentration of N2O2 to decrease to 10.0% of its initial value in the following equation... N2O5 to NO2 and O2 initial concentration is
10. ## chemistry

Butadiene, C4H6, in the gas phase undergoes a reaction to produce C8H12. The following data were obtained for the reaction. [C4H6] Time (min) 1 0 0.98 20 0.91 100 0.66 500 0.49 1000 0.32 2000 0.25 3000 Determine the order of the reaction. Order with
11. ## Chem10

The decomposition of XY is second-order in XY and has a rate constant of 0.00599 M-1s-1 at a certain temperature. If the initial concentration of XY is 0.174 M, how long (in seconds) will it take for the concentration to decrease to 0.054 M?
12. ## Chem8

The decomposition of XY is second-order in XY and has a rate constant of 0.00895 M-1s-1 at a certain temperature. If the initial concentration of XY is 0.194 M, how long (in seconds) will it take for the concentration to decrease to 0.047 M?
13. ## Chemistry

Question: the rate constant for the second order decomposition of NOBr(g) is .800 1 divided by MS at 10 degree's C. Suppose a 2.50 L beaker contains NOBr at a concentration at .0680 moles per liter. How much time does it take for 75.0 percent of the sample
14. ## MATH

what is a constant rate of change? That means the velocity changes over time in the same manner. 4,800 +3,700 =4,500 Rate of Change Is Constant You can increase or decrease the amount or concentration of a species by a constant value using a zero order
15. ## Chemistry

The decomposition reaction of A to B has a rate constant of 0.00923 M-1s-1: A → 2B If the initial concentration of A is 0.160 M, how long will it take for the concentration of A to decrease by 68.2%?
16. ## chemistry

The reaction Cl(g)+ O3(g) --> ClO(g)+ O2(g) is the first-order in both reactants. Determine the pseudo-first-order and second-order rate constants for the reaction from the data in the table below if the initial ozone concentration was ..0000000000825 M
17. ## chemistry

The reaction Cl(g)+ O3(g) --> ClO(g)+ O2(g) is the first-order in both reactants. Determine the pseudo-first-order and second-order rate constants for the reaction from the data in the table below if the initial ozone concentration was ..0000000000825 M
18. ## Chemistry

The reaction: 2 HI==> H2 + I2, is second order and the rate constant at 800 K is 9.70 x 10-2 M-1 s-1. How long will it take for 8.00 x 10-2 mol/L of HI to decrease to one-fourth of its initial concentration?
19. ## Chemistry

The rate constant for a certain reaction is = 4.30×10−3 s^-1. If the initial reactant concentration was 0.400 M , what will the concentration be after 19.0 minutes? Rate would be first order therefore I used. A=A initial*e^-kt I keep getting .0030 M
20. ## Chemistry

This problem is 1st order for half life. How long would it take for the concentration of cyclopropane to decrease to 50% of its initial value? to 25% of its initial value? Rate constant is 9.2/s I set up like this... t1/2= 0.693/9.2/s= 0.075s at 50% I
21. ## Chemistry

The rate law of a reaction, A-> B+C is given by the expression: Rate=k, where k=0.0113 mol/L min. If the initial concentration of the reactant is 0.225 mol/L, how long does it take for the concentration to decrease to 0.180 mol/L? I know i have to find
22. ## Chemistry

A zero-order reaction has a constant rate of 3.20×10^−4 M/s. If after 35.0 seconds the concentration has dropped to 9.00×10^2M , what was the initial concentration?
23. ## Chemistry

Determine the rate constant for the following second-order reaction: A=C+2D given that the initial concentration of A is .3 M and that the concentration of C increase to .01 M in 200 seconds. Express the result in terms of the rate law for the loss of A.
24. ## Chemistry

Determine the rate constant for the following second-order reaction: A=C+2D given that the initial concentration of A is .3 M and that the concentration of C increase to .01 M in 200 seconds. Express the result in terms of the rate law for the loss of A.
25. ## Chemistry

At a given temperature, a first-order reaction has a rate constant of 3.5 ´ 10–3 s–1. How long will it take for the reaction to be 24% complete? A chemical reaction that is first-order in X is observed to have a rate constant of 2.20 ´ 10–2 s–1.
26. ## Chemistry

The reaction: 2 HI==> H2 + I2, is second order and the rate constant at 800 K is 9.70 x 10-2 M-1 s-1. How long will it take for 8.00 x 10-2 mol/L of HI to decrease to one-fourth of its initial concentration? can someone please show me how to set this
27. ## chemistry

1) The activation energy of a certain reaction is 35.3 kJ/mol. At 20 degrees C, the rate constant is 0.0130 s^-1. At what temperature would this reaction go twice as fast? Answer in units of degrees Celsius. i think the answer is around 34, but i keep in
28. ## AP Chemistry

I have no idea where to start with this problem: A certain reaction has the following general form: aA -> bB At a particular temperature and (A)o = 2.00(10^-2)M, concentration versus time data were collected for this reaction, and a plot of In(A) versus
29. ## Ap Chemistry

I have no idea where to start with this problem: A certain reaction has the following general form: aA -> bB At a particular temperature and (A)o = 2.00(10^-2)M, concentration versus time data were collected for this reaction, and a plot of In(A) versus
30. ## Chemistry

The reaction 2NO2--->2NO+O2 has the rate constant k= 0.68 m-1s-1. If the initial concentration of NO2 is 9.30×10−2 M, how long it would take for the concentration to decrease to 2.00×10−2 M ? please answer and show the steps
31. ## Chemistry

Determine the rate constant for each of the following first-order reactions. In each case, write the rate law for the rate of loss of A. (a) 2 A B + C, given that the concentration of A decreases to one-fourth its initial value in 57 min (b) 2 A B + C,
32. ## Chemistry

The decomposition of hydrogen iodide on a gold surface at 150 oC HI(g) ½ H2(g) + ½ I2(g) is zero order in HI with a rate constant of 1.20E-4 Ms-1. If the initial concentration of HI is 0.575 M, the concentration of HI will be 0.116 M after seconds have
33. ## Chemistry

The decomposition of hydrogen iodide on a gold surface at 150 oC HI(g) ½ H2(g) + ½ I2(g) is zero order in HI with a rate constant of 1.20E-4 Ms-1. If the initial concentration of HI is 0.575 M, the concentration of HI will be 0.116 M after how many
34. ## Chemistry

In a given 1st order reaction A ---> products, the initial concentration of A is 0.40 M. What will be the concentration of A after 15 seconds if the half-life of the reaction is 3 seconds? I found the concentration to be 1.25 x 10-2 M But then how do I
35. ## chemistry

he decomposition of nitrogen dioxide at a high temperature is second order in this reactant. NO2(g) NO(g) + 1/2 O2(g) The rate constant for this reaction is 3.40 L/mol·min. Determine the time needed for the concentration of NO2 to decrease from 2.30 mol/L
36. ## chemistry

the concentration of a chemical degrades in water according to order kinetics. the degradation constant is 0.2 day^-1. if the initial concentration is 100.0 mg/L, how may days are required for the concentration to reach 0.14 mg/L?
37. ## chemistry

The reaction A -> B + C is 1st order w/ respet to A. It's rate const k is equal to 0.343 M/s at 273K. The initial concentration of A was 0.399 M. Calculate the concentration of B after 0.185 secs have passed.
38. ## Chemisty

A reaction of the form aA---> Products is second order with a rate constant of 0.169 L/(mol*s). If the intial concentration of A is 0.159 mol/L, how many seconds would it taje for the concentration of A to decrease to 6.07X10^-3 mol/L
39. ## Chemistry

A reaction of the form aA---> Products is second order with a rate constant of 0.169 L/(mol*s). If the intial concentration of A is 0.159 mol/L, how many seconds would it taje for the concentration of A to decrease to 6.07X10^-3 mol/L
40. ## Chemistry

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

A zero-order reaction has a constant rate of 3.40×10−4 M/s. If after 80.0 seconds the concentration has dropped to 6.00×10−2 M, what was the initial concentration?
42. ## Chemistry

2A-->B+C given that the initial concentration of A is .022M and that at 69 s, the concentration of B increases to .0095M, what is the rate constant? i know I need to find the new concentration of A at 69s, but I am having trouble with findthing this. I
43. ## Chemistry

A reaction of the form aA-----products is second-order with a rate constant of 0.225 L/(mol/s). If the initial concentration of A is 0.293 mol/L, what is the molar concentration of A after 35.6 secs?
44. ## Chemistry

Cyclopropane, C3H6, is converted to its isomer propylene, CH2=CHCH3, when heated. The rate law is first order in cyclopropane, and the rate constant is 6.0 10^-4 /s at 500°C. If the initial concentration of cyclopropane is 0.0238 mol/L, what is the
45. ## Chemistry

Consider the reaction A ==> B. If the reaction is first-order in A with the initial concentration A being 6.048M, what is the concentration of A after 1.986 seconds if the rate constant is 0.483s-1? Error tolerance: ±0.5% Can someone explain how to do
46. ## chemistry

In a reaction A to products, ,4.40 min after the reaction is started concentration of A is 0.588M. The rate of reaction at this point is rate= -change in concentration of A/change in time=2.2x10^-2Mmin^-1. Assume that this rate remains constant for a short
47. ## chemistry

The decomposition of hydrogen iodide if the equation: 2HI (g)--> H2 (g) + I2 (g) The reaction is second order and has a constant rate equal to 1, 6X10^-3 L/mol * s at 700 degrees. If the initial HI concentration in a vessel is 3.4X10 ^-2m. How many
48. ## Chemistry

The decomposition of hydrogen iodide on a gold surface at 150 oC HI(g) ½ H2(g) + ½ I2(g) is zero order in HI. In one experiment, when the initial concentration of HI was 0.206 M, the concentration of HI dropped to 3.71E-2 M after 898 seconds had passed.
49. ## Chemistry

refer to the reaction 2NH3 (g) ↔ N2 (g) + 3H2 (g), and ΔH = 92.2 kJ. 1.What will be the effect on the concentration of H2 if the temperature decreases? A. H2 concentration will decrease. B. H2 concentration will not change. C. H2 concentration will
50. ## chem

Butadiene can undergo the following reaction To form a dimer(two butadiene molecules hooked together). 2c4h8---->c8h12. The half life for the reaction at a given temperature is 5.92x10-2 sec. The reaction kinetics are second order. 1. If the initial
51. ## CHEMISTRY

A second-order reaction has a rate constant of 1.65 M–1 s–1. If the initial reactant concentration is 1.0 M, calculate the time (in seconds) required for the reaction to become 90% complete. i got 0.06734 seconds but that's incorrect i have no idea
52. ## Chemistry

So, I go to high school in Texas and we have this AP Chem lab due online tomorrow night by midnight and I need some serious help on these questions:  Lab Temp 0.2°C  Experiment Trial Time in seconds Trial 1 Trial 2 Average Time  1 1 2 256 275 268  2
53. ## Chemistry - URGENT

So, I go to high school in Texas and we have this AP Chem lab due online tomorrow night by midnight and I need some serious help on these questions:   Lab Temp 0.2°C   Experiment Trial Time in seconds Trial 1 Trial 2 Average Time   1 1 2 256 275
54. ## Chemistry - reaction kinetics

So, I go to high school in Texas and we have this AP Chem lab due online tomorrow night by midnight and I need some serious help on these questions:   Lab Temp 0.2°C   Experiment Trial Time in seconds Trial 1 Trial 2 Average Time   1 1 2 256 275
55. ## Chemistry

The first order rate constant is 1.87 x 10^-3 min^-1 at 37°C for reaction of cisplatin. Suppose the concentration of cisplatin in the bloodstream of a patient is 4.73 x 10^-4 mol/L. Calculate the concentration exactly 24 hours later.
56. ## chemistry

For the first-order reaction A => 3 B + C, when [ A]0 = 0.014 mol·L-1, the concentration of B increases to 0.017 mol·L-1 in 2.7 min. (a) What is the rate constant for the reaction expressed as the rate of loss of A? I found this to be .1923, which I
57. ## Chemistry

For the reaction 2 NO (g) + Cl2 (g) → 2 NOCl (g) If the concentration of NO is tripled, the rate of the reaction increases by a factor of nine. If the concentration of Cl2 is cut in half, the rate of the reaction is decreased to half the original
58. ## Chemistry

A first order reaction ABC → AB + C has a rate constant of 0.0125 /s. If the initial concentration of ABC is 0.500 M, what is the concentration of ABC after 5 minutes? Note: do not include units in your answer, do not use scientific notation.
59. ## Chemistry

Cyclopropane rearranges to form propene: CH2CH2CH2 --> CH2=CHCH3 by first-order kinetics. The rate constant is k = 2.74 x 10-3 s-1. The initial concentration of cyclopropane is 0.290 M. What will be the concentration of cyclopropane after 100 seconds?
60. ## chemistry

A particular reactant decomposes with a half-life of 103 s when its initial concentration is 0.397 M. The same reactant decomposes with a half-life of 213 s when its initial concentration is 0.192 M. Determine rate order and rate constant.
61. ## chemistry

On this problem I keep getting the wrong answer. I am subtracting the initial concentration of Cl2 by the equilibrium concentration then using the difference to subtract for the rest using the mole ratios. Then i used the keq constant equation of
62. ## Chemistry

The reaction NO2(g) + NO2(g) → N2O4(g) is second order with a rate constant of 0.044 /M·s at a particular temperature and pressure. If the initial concentration of NO2(g) is 0.100 M, what is the concentration of NO2 after 20 minutes?
63. ## chemistry - (Dr. Bob222)

The rate constant for a second order reaction has the value of 2.5 x 10–3 L·mol–1·s–1. If the initial concentration of reactant is 3.5 mol·L-1, what will be the molar concentration of the reactant after 2.5 minutes?
64. ## chemistry

The following data were obtained at 25° C for the reaction [1+2+2] C2H5Br + OH- C2H5OH + Br- Determine the rate law for the reaction from these data. [C2H5Br] [OH-] Rate 0.150 0.200 4.8 x 10-5 0.300 0.200 9.6 x 10-5 0.450 0.200 14.4 x 10-5 0.300 0.600
65. ## Chemistry

Hydrogen iodide decomposition via a second-order process to produce hydrogen and iodine according to the following chemical equation: 2 HI(g) -> H2 (g) + I2 (g) If it takes 489 seconds for the initial concentration of HI to decrease from 0.0693 M to
66. ## AP Chem

A first-order reaction has a rate constant of 0.547 min - 1. How long will it take a reactant concentration 0.14 M to decrease to 0.07 M? Not sure how to do this!
67. ## chemistry

The initial concentration of the a substance was 1.95 M. After 27.72 hours the concentration was 0.9750 M. After anothers 55.44 hours the concentration was 0.4875 M (total time = 83.16 hours). If another experiment were conducted in which the initial
68. ## chemistry

Suppose you have the following reaction at equilibrium: N2(g) + 3H2(g) = 2NH3(g), ΔH = −22 kcal/mol What changes are expected to occur if the temperature of the system was decreased. You may select multiple answers. The concentration of NH3(g)
69. ## chemistry kinetics

Decomposition of an organic compound A follows first order kinetics. Initial concentration of A is 2 M. If rate constant of the decomposition is 3.58 × 10^−6 min^-1 , calculate the rate after 3 hours.
70. ## chemistry

A particular reactant decomposes with a half-life of 103 s when its initial concentration is 0.397 M. The same reactant decomposes with a half-life of 213 s when its initial concentration is 0.192 M. what is the reaction order and rate constant
71. ## Chemistry

The rate constant for a certain reaction is = 8.00×10−3 . If the initial reactant concentration was 0.400 , what will the concentration be after 16.0 minutes?
72. ## Chemistry

The rate constant for a certain reaction is k=8.90×10^−3 s^-1. If the initial reactant concentration was 0.400M, what will the concentration be after 13.0 minutes?
73. ## Chemistry!

The rate constant for a certain reaction is k = 5.00×10−3 s-1 . If the initial reactant concentration was 0.950 M , what will the concentration be after 8.00 minutes?
74. ## Chemistry

1. The following data was collected for the reaction between hydrogen and nitrogen monoxide. The time recorded corresponds to a N2 concentration change of 5.3 x 10-4 M. 2H2(g) + 2NO(g)  2H2O(g) + N2(g) Trial [H2], M [NO], M Time, s 1 0.01 0.02 74 2
75. ## Chemistry

The rate constant for the reaction is 0.710 M–1·s–1 at 200 °C. A ---> products If the initial concentration of A is 0.00390 M, what will be the concentration after 595 s?
76. ## chemistry

Need some help. have the A part of the question but do not know how to set B or C. Butadiene (C4H6) reacts with itself to form a dimer with the formula C8H12. The reaction is second order in butadiene. If the rate constant at a particular temp is 0.04/(M
77. ## Calc

Write a deferential equation describing the given situation. The rate at which the concentration of a drug in the bloodstream decreases is proportional to the concentration. Let Q(t) be the concentration of the drug at any time t and k be a positive
78. ## Chemistry

I've tried this problem over and over again, but im not getting the right answers! This is the problem....... Dinitrogen pentoxide, N2O5, decomposes when heated in carbon tetrachloride solvent. N2O5 ¨ 2 NO2 + 1/2 O2(g) If the rate constant for the
79. ## Chemistry

For the following reaction 2NO2 -> 2NO +O2 is second order reaction. If the initial concentration of NO2 is 0.098M and the initial rate of disappearance is 2.72e-3 M/sec , what is the value of the rate constant?
80. ## Chemistry

The rate constant for this first-order reaction is 0.440 s-1 at 400 C. A to products How long in seconds would it take for concentration of A to decrease from 0.740 M 0.290 M?
81. ## chemistry

The rate constant for this first-order reaction is 0.320 s–1 at 400 °C. A--> Products How long (in seconds) would it take for the concentration of A to decrease from 0.830 M to 0.220 M?
82. ## Chemistry

Hey there! I have these two questions for my chemistry class, and I am a little confused on how I should go about solving them. If someone could give me the steps necessary to solve these problems I would be most appreciative. 1.) p-Toluenesulfinic acid
83. ## science

Which of the following terms are present in the rate law? A. The rate constant, the concentration of the reactants, and the order of the reactants B. The rate constant and the concentration of the reactants C. The rate constant and the temperature of the
84. ## chemistry

Which of the following terms are present in the rate law? A. The rate constant, the concentration of the reactants, and the order of the reactants B. The rate constant and the concentration of the reactants C. The rate constant and the temperature of the
85. ## chemistry help?!

Which of the following terms are present in the rate law? A. The rate constant, the concentration of the reactants, and the order of the reactants B. The rate constant and the concentration of the reactants C. The rate constant and the temperature of the
86. ## Chem

Estimate the equilibrium constant for the weak base (CH3)2NH, if a 1.59×10-2 M aqueous solution of (CH3)2NH has a pOH 2.58 (make an exact calculation assuming that initial concentration is not equal to the equilibrium concentration). (CH3)2NH + H2O =
87. ## Chemistry

The rate constant for this first order reaction is 0.440s-1at 400 C. A to products How long(in seconds) would it take for the concentration of A to decrease from 0.740 M to 0.290 M?
88. ## Chem 132

The rate constant for this first-order reaction is 0.650 s–1 at 400 °C. A------> Products How long (in seconds) would it take for the concentration of A to decrease from 0.660 M to 0.350 M?
89. ## chemistry

In the presence of a tungsten catalyst at high temperature, the decomposition of ammonia to nitrogen and hydrogen is a zero order process. If the rate constant at a particular temperature us 3.7x10^-6 mol. How long will it take for an ammonia concentration
90. ## chemistry

A) Calculate the hydrogen-ion concentration of a 5.45*10^-4 M H2CO3, solution, noting that Ka is bigger than Kb. B)What is the concentration of CO3^2-? after finding the concentration to A), do i use that concentration (M) as the initial M for CO3^2-?
91. ## CHEM

Calculate the equilibrium constant for the weak base CH3NH2, if a solution of the base with an initial concentration of 7.05×10-4 M has a [CH3NH3+] of 0.000379 M (make an exact calculation assuming that initial concentration is not equal to the
92. ## chemistry

Calculate the equilibrium constant for the weak base C5H5N, if a solution of the base with an initial concentration of 5.74×10-3 M has a [C5H5NH+] of 0.00000283 M (make an approximate calculation assuming that initial concentration is equal to the
93. ## Chemistry

Administratium bromide (AdBr) decomposes readily at temperatures exceeding 37°C. The figure below shows how the rate of reaction varies with the concentration of AdBr. The rate, r, is in units of M s-1 and the concentration of AdBr, c, is in units of M
94. ## west prep

for a zero order how long will it take for the concentration of reactant tp fall to one eight is original value if it takes 15.5 minutes for concentration to be reduced to half its original value
95. ## chem

The rate data from a chemical reaction shows that doubling the concentration of A with the concentration of B remaining constant causes the rate to increase by a factor of four. What is the reaction order for [A]? a. 0 b. 0.5 c. 1 d. 2 e. 3
96. ## Chemistry

The gas phase decomposition of dinitrogen pentoxide at 335 K N2O5(g) 2 NO2(g) + ½ O2(g) is first order in N2O5. During one experiment it was found that when the initial concentration of N2O5 was 0.218 M, the concentration of N2O5 dropped to 2.96E-2 M