Yttrium-90 (90Y^{90}\text{Y}90Y) is a radionuclide used in radiation therapy for treating liver cancer. It has a half-life of 64.0 hours64.0\text{ hours}64.0 hours.
What is the total activity of a sample containing 8.5 ng8.5\text{ ng}8.5 ng of yttrium-90?
(Molar mass of 90Y=90.0 g mol−1^{90}\text{Y} = 90.0\text{ g mol}^{-1}90Y=90.0 g mol−1; Avogadro constant NA=6.02×1023 mol−1N_A = 6.02 \times 10^{23}\text{ mol}^{-1}NA=6.02×1023 mol−1)
1.7×105 Bq1.7 \times 10^5\text{ Bq}1.7×105 Bq
1.7×108 Bq1.7 \times 10^8\text{ Bq}1.7×108 Bq
1.7×1011 Bq1.7 \times 10^{11}\text{ Bq}1.7×1011 Bq
6.2×1011 Bq6.2 \times 10^{11}\text{ Bq}6.2×1011 Bq
