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

Answer 1

k = 0.693/t_1/2
Substitute and solve for k and use k in the equation below.

ln(No/N) = kt
No = 28
N = ?
k from above
t = 84 days.

Answer 2

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?