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

the molecules move in straight line until they collide with each other or with the walls of the container. collisions are perfectly elastic; when two molecules collide, they change their directions and kinetic energies, but the total kinetic energy is conserved.

explanation: