uranium - 232 has a half - life of 68.9 years. a sample from 206.7 years ago contains 1.40 g of uranium…

Answer:

11.2 g

Explanation:

Step1: Calcular el número de vidas medias

$n=\frac{206.7}{68.9}=3$

Step2: Aplicar la fórmula de decaimiento radioactivo

$N = N_0(\frac{1}{2})^n$, donde $N = 1.40$ g, $n = 3$. Re - arreglamos la fórmula para $N_0$: $N_0=\frac{N}{(\frac{1}{2})^n}$. Sustituyendo valores, $N_0=\frac{1.40}{(\frac{1}{2})^3}=\frac{1.40}{\frac{1}{8}}=1.40\times8 = 11.2$ g.