# Chemistry

posted by .

Cobalt-60, which undergoes beta decay, has a half-life of 5.26 yr. How many beta particles are emitted in 190s by a 3.10mg sample of Co-60? What is the activity of the sample in Bq?

• Chemistry -

k = 0.693/t1/2
k has units of yr^-1

Convert 3.10 mg sample to moles.
moles = grams/molar mass.

Convert moles to atoms.
# atoms = moles x 6.02E23

rate = k*Number atoms
This will give you the rate in a year (decays per year). Convert to 190 seconds for the number of decays in that time.

Divide by 190 seconds to obtain dps (decays per second). That will be the number of Bq.

## Respond to this Question

 First Name School Subject Your Answer

## Similar Questions

1. ### Chemistry (Grade 11)

A radioactive sample of 141Cs has a half-life of 32.5 days. In a sample that contains 8.00*10^7 nuclei of 141Cs, how many beta particles per second will be emitted?
2. ### Chemistry

Write a nuclear equation for the following: Iodine 131 undergoes beta decay two times Plutonium 239 is an alpha emitter Th 234 undergoes beta decay once and then alpha decay How do I go about writing nuclear equations?
3. ### Chemistry

Cobalt-60, which undergoes beta decay, has a half-life of 5.26 yr. How many beta particles are emitted in 190s by a 3.10mg sample of Co-60?
4. ### Chemistry

Cobalt-60, which undergoes beta decay, has a half-life of 5.26 yr. How many beta particles are emitted in 190s by a 3.10mg sample of Co-60?
5. ### Chemistry

Cobalt-60, which undergoes beta decay, has a half-life of 5.26 yr. How many beta particles are emitted in 190s by a 3.10mg sample of Co-60?
6. ### Chemistry

A 25.40 g sample of water containing tritium,(3/1)H , emits 1450 beta particles per second. Tritium is a weak beta emitter, with a half-life of 12.3 yr. What fraction of all the hydrogen in the water sample is tritium?
7. ### chem

Cobalt-60, which undergoes beta decay, has a half-life of 5.26 yr. (a) How many beta particles are emitted in 47.0 s by a 2.39-mg sample of 60Co?
8. ### chemistry

Strontium-90 decays through the emission of beta particles. It has a half-life of 29 years. How long does it take for 80% of a sample of strontium-90 to decay?
9. ### Physics

A radioactive isotope of Bismuth undergoes Beta Decay with a half-life of 22 days. How long (in days) will it take the Activity (A) of the sample to decrease to one-ninth of its original value?
10. ### Chemistry

Given a 800 mg sample of Thorium-231 decomposes via beta emission with a half life of 25.5 hours, how long would it take, in days, for the sample to decay down to 25 mg?

More Similar Questions