Suppose the half life of element K is 20 minutes. If you have 200 g sample of K, how much of element K will be left after 60 minutes?

1 Answer
Mar 31, 2016

Answer:

#25color(white)(i)g#

Explanation:

Recall that the formula for half-life is:

#color(blue)(|bar(ul(color(white)(a/a)y=a(b)^(t/h)color(white)(a/a)|)))#

where:
#y=#final amount
#a=#inital amount
#b=#growth/decay
#t=#time elapsed
#h=#half-life

To find the amount of the sample left after #60# minutes, substitute your known values into the equation.

#y=200(1/2)^(60/20)#

Solve for #y#.

#y=200(1/2)^3#

#y=200(1/8)#

#color(green)(|bar(ul(color(white)(a/a)y=25color(white)(i)gcolor(white)(a/a)|)))#