Question

Element X decays radioactively with a half life of 10 minutes. If there are 270 grams

of Element X, how long, to the nearest tenth of a minute, would it take the element to
decay to 13 grams?

Answer 1

Below

Explanation:

t1/2 = 10 min

gm remaining = 270 (1/2)^n where 'n' is the number of 10 minute half lives

13 = 270 (1/2)^n

13/270 = (1/2)^n LOG both sides and solve for 'n'

log (13/270) / log (1/2) = n = 4.376 half lives

4.376 hl * 10 min/ hl =43.8 min