The isotope chromium-51 has a half-life of 28 days. If the original sample had a mass of 28.0 grams, what mass of the chromium-51 sample remains after 84 days?

1 Answer
May 30, 2016

3.50g3.50g

Explanation:

To find the mass of the chronium-51 sample that remains after 8484 days, we can use the half-life formula.

Recall the half-life formula:

color(blue)(|bar(ul(color(white)(a/a)A=A_0(1/2)^(t/h)color(white)(a/a)|)))

where:
A=final amount
A_0=initial amount
t=time elapsed
h=time for half of initial amount to remain after decay (also known as half-life)

Plugging in our known values,

A=28.0g(1/2)^((84color(white)(i)"days")/(28color(white)(i)"days"))

A=color(green)(|bar(ul(color(white)(a/a)color(black)(3.50g)color(white)(a/a)|)))