The hall-life for the radioactive decay of Ce-141 is 32.5 days. If a sample has an activity of 3.9 uCi after 195 d have elapsed, what was the initial activity, in microcuries, of the sample?
Express your answer using two significant figures.

Ahypothrticalax type of ceramic material is known to have a density of 2.10 g/cm3 and a unit cell of cubic symmetry with a cell edge length of 0.57 nm. the atomic weights of the a and x elements are 28.5and 30.0 g/mol, respectively. on the basis of this information, which of the following crystal structures is (are) possible for this material: sodium chloride, cesium chloride, or zinc blende

Determine the empirical formula for succinic acid that is composed of 40.60% carbon, 5.18% hydrogen, and 54.22% oxygen.

What atom has the largest atomic radius