A sample of a radioactive isotope initially contains 20 x 10^10 atoms. After 16 days, 5 x 10^10 atoms remain. what is the half-life of the isotope?

A)12 days
B)20 days
C)10 days
D)16 days
E)8 days

Why is nh3 classified as a polar molecule

Consider the following reactions. (note: (s) = solid, (l) = liquid, and (g) = gas.) mg(s) + ½o2(g) → mgo(s) + 146 kcal/mole h2(g) + ½o2(g) → h2o(g), δh = -57.82 kcal/mole what type of reaction is represented by the previous two examples?

Select the word from the list that best fits the definition the nuclear family into which a person is born or adopted.