The isotope 'sr has a half-life of 28.8 years. what is the activity, measured in atoms/second, of a 50 mg sample of "sr? (10 pts.)

The activity of 50mg of Sr is

Explanation:

Every nuclear disintegration follows the first order rate, thus the half-life (t1/2) is where k is the constant of the reaction.

Considering 1 year equals 3.15x107 seconds

For Sr with t1/2 = , the constant of the reaction is

The activity (A) of a nucleus is where N is the number of nucleus. Sr molecular mass is 87.6g/mol and every mol contains 6.023x1023 atoms, thus

Therefore, the activity of 50mg of Sr is