Question
Asked Oct 24, 2019
3 views

How many of the nuclei of a radioactive sample containing 2048 nuclei decay in 3 years, if it's half life is given to be 6 months ? 

check_circle

Expert Answer

Step 1

Half life of a radioactive sample is the time in which half of the sample is decayed i.e. 50% of the radioactive sample remains.

Radioactive decay follows first order kinetcsand hence, half life is independent of the initial concentration.

Step 2

Half life of given sample is 6 months

It means after every 6 months, the radioactive nuclei present in the sample will be reduced to half.

Number of radioactive nuclei present intially = 2048

After 6 months (one half life) , radioactive nuclei remaining = 2048/2 = 1024

After 1 years (two half lives), radioactive nuclei remaining = 1024/2 = 512

After 1 year and 6 months (three half lives), radioactive nuclei remaining = 512/2 = 256

After 2 years (four half lives), radioactive nuclei remaining = 256/2 = 128

After 2 years and 6 months (five half lives), radioactive nuclei remaining = 128/2 = 64

After 3 years (six half lives), radioactive nuclei remaining = 64/2 = 32

Hence, nuclei decayed after 3 years = Initial nuclei - Nuclei remaining after 3 years = 2048 - 32 = 2016

Step 3

Alternative method:

A/Ao = (1/2)n

Here, A is Nuclei remaining after 'n' half lives

Ao is initial number of nuclei

'n' is number of half lives

Now, in 3 years, number of half lives = 6.

So, 'n' = 6

Ao = 2048

Substituting the values,

(A/2048) = ...

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

Science

Chemistry

Chemical Kinetics

Related Chemistry Q&A

Find answers to questions asked by student like you

Show more Q&A add
question_answer

Q: A grain of sand weighs 7.7 × 10−4 g. How many formula units of silicon dioxide, SiO2, are in one san...

A: The mass of one formula unit of SiO2 = 60.08 g/mol.

question_answer

Q: Using the reaction and Ligand 6, how does the HNMR tell us the product was formed?

A: In the reactant formaldehyde is there.

question_answer

Q: Select the sp appropriate atoms by clicking them so that they are highlighted. Н H H H -C=c=C-C H oN...

A: Hybridization of carbon atom that is connected to only one double bond is sp2 ,and carbon atom that ...

question_answer

Q: What is a good method to memorize the solubility rules?

A: Almost all the nitrates are soluble.Carbonates are mostly insoluble.Sulfides of most cations are ins...

question_answer

Q: catalytic hydrogenation ( or deuteration) adds H2 (or D2) by a syn electrophilic addition. Which ans...

A: The product of syn-addition of D2 to (E)-2-pentene and (Z)-2-pentene is to be determined.

question_answer

Q: N2(g) + 3H2(g) → 2NH3(g) Suppose that a particular moment during the reaction, molecular hydroge...

A: For the given reaction,N2 + 3H2 → 2NH3The expression for the rate of the disappearance of reactants ...

question_answer

Q: When performing a flame test you are told that a rubidium solution will produce a violet color, but ...

A: Click to see the answer

question_answer

Q: what elements in everyday life involve chemistry?

A: A chemical element refers to a substance whose atoms have the same number of protons or same atomic ...

question_answer

Q: Write a net ionic equation for the reaction that occurs when excess aqueous nitric acid is combined ...

A: A chemical equation that shows the number of species or ions participating in the reaction, is known...