Phosphorus-32 has a half-life of 14.3 days. How much of a 4 mg sample of phosphorus-32 will remain after 71.5 days

If the particles in a sample of matter have an orderly arrangement and move only in place, the sample is a

How many moles of magnesium is 3.01 x10^22 atoms of magnesium?

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?