Answer: r = -0.14
Step-by-step explanation:
[tex]K=K_o\cdot e^{rn}\quad \text{where;}\\\bullet K\ \text{is the final amount of Kristinite}\\\bullet K_o\ \text{is the initial amount of Kristinite}\\\bullet r\ \text{is the rate of decay}\\\bullet n\ \text{is the number of seconds the decay has occurred}\\\\\\\text{Given:}\\\\K: \dfrac{1}{2}K_o\\\\r: unknown\\\\n: 2\\\\\\K=K_o\cdot e^{rn}\\\\\\\dfrac{1}{2}K_o=K_o\cdot e^{r(5)}\\\\\\\dfrac{1}{2}=e^{5r}\\\\\\ln\dfrac{1}{2}=5r\\\\\\\dfrac{ln\dfrac{1}{2}}{5}=r\\\\\\-0.14=r\\[/tex]
