Question

I WILL GIVE BRAINLIEST

Answer 1

Answer:

5.75 g.

Explanation:

• It is known that the decay of isotopes of Pb-189 obeys first order kinetics.

• Also, it is clear that in first order decay the half-life time is independent of the initial concentration.

• The half life time of Pb-189 decay = 20 days.

• Thus, 60 hours represent (60/20) 3 half-lives.

∴ 46 g →(first half-life) 23 g →(second half-life) 11.5 g →(third half-life) 5.75 g.

• So, The amount remained is 5.75 g after 3 half-lives (60 days).