Question #d1146
1 Answer
Explanation:
You can't answer this question without knowing the half-life of carbon-14, so look that up before doing anything else.
You'll find it listed as
t_"1.2" = "5730 years"t1.2=5730 years
https://en.wikipedia.org/wiki/Carbon-14
Now, a radioactive isotope's nuclear half-life tells you the time needed for half of an initial sample to undergo radioactive decay.
In other words, the amount of this radioactive isotope is halved with the passing of every half-life.
So, let's say that you start with an unknown amount of carbon-14, let's say
A_ (1 xx t _"1/2") = A_0 * 1/2 = A_0/2 -> " after 5730 years"A1×t1/2=A0⋅12=A02→ after 5730 years
After another period of time equal to one half-life passes, you will be left with
A_ (2 xx t_ "1/2") = A_0/2 * 1/2 = A_0/4 ->" after 2" xx "5730 years"A2×t1/2=A02⋅12=A04→ after 2×5730 years
This means that after
2 xx "5730 years" = "11460 years"2×5730 years=11460 years
pass, the sample of carbon-14 will be down to
Since this is how much time passed since the plant died, you can say that
Therefore, you will have
"initial mass" = 4 xx "0.25 pg" = color(darkgreen)(ul(color(black)(1.0 color(white)(.)"pg")))
The answer is rounded to two sig figs, the number of sig figs you have for the mass of carbon-14 that remains after
