What are some first order half life practice problems?
1 Answer
Feb 14, 2017
Cobalt-60 has a half-life of 5.26 years.
a) Calculate the first-order rate constant.
b) If 20% decays, how much time did it take?
c) Write the rate law that describes this process.
d) Determine the initial rate of the process if one starts with
a) From the first-order half-life:
#t_"1/2" = ln2/k#
#=> color(blue)(k) = ln2/t_"1/2" = ln2/"5.26 yrs" = color(blue)("0.1318 yrs"^(-1))#
b) From the integrated rate law:
#ln(([A])/([A]_0)) = -kt#
#color(blue)(t) = -ln(([A])/([A]_0))/(k) = -ln((0.2cancel([A]_0))/(cancel([A]_0)))/(k)#
#= -ln(0.2)/("0.1318 yrs"^(-1)) = color(blue)("3.268 yrs")#
c)
d)