試題詳解

24. Phosphorus-32 (P-32) is a commonly used radioactive nuclide in biochemical research, particularly in studies of nucleic acids. The half-life of P-32 is 14.3 days. What mass of P-32 is left from an original sample of 175 mg of Na₃ ³²PO₄ after 35.0 days? Assume the atomic mass of 32-P is 32.0.
(A)6.22 mg
(B)62.20 mg
(C)0.12 mg
(D) 1.24 mg
(E)12.44 mg