Question

Starting with 1.20 g A, what is the mass of A remaining undercomposed after 1.00h? ( t1/2= 16 min)

Answer 1

you can simplify this formula: \[A=A _{0}e ^{-kt}\]

to this:

\[A=A _{0}(\frac{ 1 }{ 2 })^{\frac{ t }{ t _{1/2} }}\]

A=amount after time elapsed
Ao=initial amount
t= time
t1/2= half life

Answer 2

you can also approximate 16min as 1/4 of 1 hour, so 4 half-lives will pass over that time span. 1/16 of the 1.20g will remain after 1 hour (more or less)