Asked Oct 25, 2019
One of the radioactive isotopes used in medical treatment or analysis is iodine-131. The half-life of iodine-131 is 8 days. How much time is required for the activity of a sample of iodine-131 to fall to 12.5 percent of its original value?

Expert Answer

Step 1

The relationship between the decay constant and the half-life period is given below.


Image Transcriptionclose

0.693 t12

Step 2

The decay constant of I-131 can be calculated as shown below.


Image Transcriptionclose

0.693 0.693 0.0866 days 8 days λ- t2

Step 3

The nuclear disintegration time can be calculated as shown below.


Image Transcriptionclose

2.303 N log N t = Where, tis a time period of disintegration N is a initial amount of radioactive substance 0 N, is a amount of radioactive substance at time t


Want to see the full answer?

See Solution

Check out a sample Q&A here.

Want to see this answer and more?

Solutions are written by subject experts who are available 24/7. Questions are typically answered within 1 hour.*

See Solution
*Response times may vary by subject and question.
Tagged in



Inorganic Chemistry

Related Chemistry Q&A

Find answers to questions asked by student like you
Show more Q&A

Q: Consider the following unbalanced net ionic redox equation. VO2+ + SO32- ---> V3+ + SO42- Name th...

A: An oxidizing agent is the species which gains electrons and is reduced in a chemical reaction.Oxidiz...


Q: how many grams of a solution that is 5.2 sucrose by mass are needed to obtain 18 g of sucrose

A: Given that mass by the percentage of the solution is 5.2, and the mass of solute, sucrose, is 18 g.T...


Q: Calculate the volume in liters of a 0.125 M barium acetate solution that contains 175.g of barium ac...

A: The given mass of barium acetate, 175.g has to be converted into moles.


Q: For the nitrogen fixation reaction 3H2(g) + N2(g) <--> 2NH3(g), Kc = 6.0 × 10–2 at 500°C. If 0...

A: The given reaction


Q: Predict the products and what is the reaction mechanism?

A: In the presence of a strong base, the ratio of eliminated product increases when there is an increas...


Q: Determine the pH of an HF solution of each of the following concentrations. In which cases can you n...

A: (a)ICE table for the reaction is given below.


Q: Which hybridization scheme in Valence Bond theory gives rise to: trigonal planar electronic geometry...

A: Hybridization scheme in Valence Bond theory gives rise to:


Q: It takes 54.0 J to raise the temperature of an 11.5 g piece of unknown metal from 13.0 Celcius to 24...

A: The relationship between heat required and specific heat of a substance is given below.


Q: What is the general formula for a noncyclic alkane? C?H a. b. If a noncyclic alkane contains 15 carb...

A: The general formula for noncyclic alkane is