The curie (Ci) is a commonly used unit for measuring nuclear radioactivity: 1 curie of radiation is equal to 3.7x10¹⁰ decay events per second (the number of decay events from 1 g of radium in 1 s).
What mass of Na₂ ³⁸so₄ has an activity of 14.5 mCi? Sulfur-38 has an atomic mass of 38.0 and a half-life of 2.87 h. ______ ng