The half-life for a first-order reaction is 32s. What was the original concentration if, after 2.0 minutes, the reactant concentration is 0.062

Md Ariful Islam

0 like 0 dislike
1 views
Share with your friends

1 Answers

Md Ariful Islam

Call

Half life = 32 s

use relation between rate constant and half life of 1st order reaction

k = (ln 2) / k

= 0.693/(half life)

= 0.693/(32)

= 2.166×10^-2 s-1

we have:

[A] = 0.062 M

t = 2.0 minutes = 2×60 = 120 s

k = 2.166×10^-2 s-1

use integrated rate law for 1st order reaction

ln[A] = ln[A]o - k×t

ln(0.062) = ln[A]o - 2.166×10^-2×120

ln[A]o = -2.780621 + 2.166×10^-2×120

ln[A]o = -0.181871

[A]o = 0.834 M

Answer: 0.834 M

0 like 0 dislike
1 views
Talk Doctor Online in Bissoy App
Different radioisotopes have different half-lives. For example, the half-life of carbon-14 is 5,700 years, the half-life of uranium- 235 is 704 million years, the half-life of potassium- 40 is 1.3 billion years, and the half-life of rubidium-87 is 49 billion years. a. Why wouldn't you use an isotope with a half-life similar to that of carbon-14 to determine the age of the Solar System? b. The age of the universe is approximately 14 billion years. Does that mean that no rubidium- 87 has decayed yet?

a. You wouldn't use an isotope with a half-life similar to that of carbon-14 to determine the age of the Solar System because the timescale involved in the formation of...

1 Answers 1 views
The reactant concentration in a first-order reaction was 9.70×10<sup>−2</sup>mol L after 25.0 s and 5.70×10<sup>−3</sup> mol L after 85.0 s . What is the rate constant for this reaction?

The integrated rate law for the first-order reaction A → products is ln[A]_t = -kt + ln[A]_0. Because this equation has the form y = mx + b, a plot...

1 Answers 1 views
The reactant concentration in a second-order reaction was 0.670mol L after 205 s and 5.00×10<sup>−2</sup> mol L after 900 s . What is the rate constant for this reaction?

The integrated rate law for the second-order reaction A → products is 1/[A]_t = kt + 1/[A]_0. Because this equation has the form y = mx + b, a plot...

1 Answers 1 views
Suppose you have an element with a Radioactivity of 175 Rad. What will be the resulting Radioactivity if it undergoes its a)1st half-life? b)2nd half-life? and c)5th half-life? with solution

a) 87.5 Radb) 43.75 Radc) 5.46 Rad

1 Answers 1 views
a reaction of second order with respect to a reactant.how is the rate of reaction affected if the concentration of the reactants is reduced half? what is the unit of rate constant of such reaction?

Look in your text book for the 2nd order chemical reaction (shown below) and plug n chug fake numbers into [A], the concentration, t (time in seconds), and A0 and...

1 Answers 1 views
The first-order decomposition of N2O at 1000 K has an initial concentration of 10.9 M. If the concentration after 9.6 s is 7.4 X 10^-3 M, what is the half life?

For the first-order reaction log([A]0/[A]) = kt/2.303 and t1/2 = 0.693/kFind klog (10.9/7.4*10-3) = k*9.6/2.303k = 0.76 s-1Find t1/2t1/2 = 0.693/0.76 = 0.912 sAnswer: 0.912 s

1 Answers 1 views
27. The half life for a first order reaction is 5 x 104 s. What percentage of the initial reactant will react in 2 hours? Calculate

t(1/2) = 5 x 10^4 - half life for a first orderreaction t(1/2) = ln2/K K = ln2/t(1/2) K = ln2/ 5 x 10^4 = 1.38 x 10^-5 ln(Cx/Co) =...

1 Answers 1 views
The half-life for a first-order reaction is 32 sec.What was the original concentration if,after 2.0 minuites, the concentration is 0.062 M ?

The half life is the time required for the concentration to drop to one-half its original value. 2 minutes is 2*60= 120 sec.If you have 120 sec and time of...

1 Answers 1 views
The rate constant of a zero-order reaction is 0.2 (mol/L) hour-1. What will be the initial concentration of the reactant if after an hour its concentration is 0.089 mol/L?

k=([C]_0-[C])/t [C]_0-[C]=k∙t [C]_0=k∙t+[C]=0.2∙1+0.089=0.289 mol/l Answer: 0.289 mol/L.

1 Answers 1 views
The reaction A + B + C &gt; D + E is first order for reactant A, first order for B, and second order for C. What is the rate law equation for this reaction?

A first-order reaction has a rate proportional to the concentration of one reactant. rate=k[A], rate=k[B] A second-order reaction has a rate proportional to the product of the concentrations of two...

1 Answers 1 views
X