Question

Question 19 of 20 > 32P is a radioactive isotope with a half-life of 14.3 days. If you currently have 27.5 g of 32p, how much 2P was present 3.00 days ago?

Answer 1

The required time for a substance to reduce to half of its original value is called as half life. So

$t\tfrac{1}{2}= 14.3 days$

Amount of 32P present currently

A0 amount of 32P present after 3 days ago

$A= A_{0}*(0.5)^{\frac{t}{t\tfrac{1}{2}}}$

$A_{0}=\frac{A}{(0.5)\frac{t}{t\tfrac{1}{2}}}$

$A_{0}=\frac{27.5}{(0.5)^{\frac{3}{14.3}}}$

A0 amount of 32P present after 3 days ago = 31.80 g.