A sealed vial initially contains 1.00 g of radioactive isotope P (molar mass 60 g mol⁻¹)
CHEMISTRY · Multi-part · US High School · Chemistry · Atomic Structure & Nuclear · Atomic Structure & Nuclear
Problem
A sealed vial initially contains 1.00 g of radioactive isotope P (molar mass 60 g mol⁻¹). Isotope P decays to isotope Q, which subsequently decays to stable isotope R. The half-life of P is 3.0 d, and the half-life of Q is 0.50 d. No isotopes Q or R are present at t = 0.
(a) Calculate the fraction of P atoms that remain after 9.0 d.
(b) Assume that by t = 9.0 d every atom of Q produced up to that instant has already decayed completely to R. Under this approximation, determine the number of moles of isotope R present in the vial at t = 9.0 d.