# Chemistry

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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 will be in yr^-1.
Convert 310 mg Co to g, then to moles. moles = grams/atomic mass.
moles x 6.02E23 = # atoms.
Rate = # atoms x k(from above) = decays per year.
Convert that to 190 sec.
Convert that to decays per sec (dps) and that will be # Bq.

• Chemistry -

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