Question

After 2238.6 years, how much of an original
1.15 g of radium-226 remains? Its half-life is
1599 years.

Answer 1

We need to know how mamy half-life periods arę passed

n = 2238.6/1599 = 1.4

Then we have the equation:

0.5^1.4= x

Where x is percent of radium-226 remains

x = 0.379

Then

m = m₀*x = 1.15*0.379 = 0.436 g