A radioactive-like first order decay of a drug follows $[A] \propto$ mass. A $8.0 g$ sample has a half-life of $10 min$ . Find the mass remaining after $45 min$ in grams (two decimals).

Numerical answer type, answer in g, tolerance 0.01.

Answer: 0.3536 g

45 min

4.5

half-lives. Mass left

= 8.0 \times (1/2)^{4.5} = 8.0 \times 0.04419 = 0.3536 g

, i.e.

0.35 g