Question

Radium-223 has a half-life of 11.0 days. How much of a 60.0 mg sample of Ra-223 is still active after 44.0 days?

Answer 1

Answer:

The answer to your question is 3.75 mg

Explanation:

Data

Radium-223

half-life = 11 days

mass = 60 mg

total time = 44 days

Process

1.- Draw a chart to start the calculation

                Mass           Number of days      Half-lives

                60 mg                    0                           0

                30 mg                    11                            1

                 15 mg                    11                            2

                7.5 mg                    11                           3

               3.75 mg                   11                           4

        Total number of days   44

       Mass active after 44 days = 3.75 mg