A 50.0-gram sample of 16N decays to 12.5 grams in 14.4 seconds. What is its half-life?

If anyone would be able to me out with these three questions it would be these are from the chem 2202 course.

Amixture initially contains a, b, and c in the following concentrations: [a] = 0.300 m , [b] = 1.05 m , and [c] = 0.550 m . the following reaction occurs and equilibrium is established: a+2b⇌c at equilibrium, [a] = 0.140 m and [c] = 0.710 m . calculate the value of the equilibrium constant, kc.

Which three statements represent the benefits of performing experiments using computer simulations?