Question

If an 900.0 g sample of radium-226 decays to 225.0 g of radium-226 remaining in 3,200 years, what is the half-life of radium-226?

Answer 1

@Abhisar

Answer 2

@JFraser

Answer 3

Use the first-order integrated rate law:

\(\large ln[A]_t=-kt+ln[A]_o\)

where \(ln[A]_o\) is the initial concentration of the substance
\(k\) is the decay constant
\(t\) is time
\(ln[A]_t\) is the concentration of substance at time \(t\)


then use: \(\large t_{1/2}=\dfrac{ln(2)}{k}\).

\(t_{1/2}\) is the half-life

Answer 4

@JFraser

Answer 5

@aaronq i got a question about this

Answer 6

what is it?

Answer 7

what is k? actually how do i find k?

Answer 8

k is the decay constant, you find it by plugging in the rest of the variables.

when you have any equation, you need to know all but one of the variables. You plug these in and solve for the unknown - which would be k in this case.

Answer 9

You may be more familiar with the equaiton written like this

\(\large [A]_{t}=[A]_0*e^{-kt}\)

but it's the same thing, it's just rearranged

Answer 10

1600?

Answer 11

what is 1600?