Question

Plz Help A radioisotope has a half-life of 5.50 min and an initial decay rate of 7200 Bq. What will be the decay rate after 22 min? Show all work and include units of measure.

A radioisotope has a half-life of 5.50 min and an initial decay rate of 7200 Bq. What will be the decay rate after 22 min? Show all work and include units of measure.


The mass of an isotope of oxygen is 17.99161 u. It has 8 protons, 8 electrons, and 10 neutrons. What is its mass defect? Show all work.

Answer 1

450 Bq, 0.15325u

Step-by-step explanation:

Half life equation:

A = A₀ (½)^(t / T)

A = (7200 Bq) (½)^(22 min / 5.50 min)

A = 450 Bq

Mass defect is the difference between the sum of the proton and neutron masses and the isotope mass.

The mass of a proton is 1.007276u, and the mass of a neutron is 1.008665u.

So the mass defect is:

(8 × 1.007276u + 10 × 1.008665u) − 17.99161u

0.15325u