Question

uranium-232 has a half-life of 68.8 years. after 344.0 years how much uranium-232 will remain from a 125.0g sample

Answer 1

4 grams

Step-by-step explanation:

A = A₀e^⁻kt

A₀ = 125.0 grams

k= 0.693/t(1/2) = (0.693/68.8) yrs⁻¹ = 0.01 yrs⁻¹

t = 344.0 years

A = 125.0g·[e^-(0.01yrs⁻¹)(344.0yrs)] = 125(0.032)grams = 4.000g (4 sog. figs. based on A₀ = 125.0 grams)

Answer 2

B. 3.13 g

Hope this helps