Answer:
0.125 g
Explanation:
In a first-order decay, the formula for the amount remaining after n half-lives is
[tex]N = \frac{N_{0}}{2^{n}}[/tex]
where
N₀ and N are the initial and final amounts of the substance
1. Calculate the number of half-lives.
If [tex]t_{\frac{1}{2}} = \text{14.0 da}[/tex]
[tex]n = \frac{t}{t_{\frac{1}{2}}} = \frac{\text{84.0 da}}{\text{14.0 da}}= \text{6.00}[/tex]
2. Calculate the final mass of the substance.
[tex]\text{N} = \frac{\text{8.00 g}}{2^{6.00}} = \frac{\text{8.00 g}}{64.0} = \text{0.125 g}[/tex]
