Please help ! After 4.00 years, 2.000 g of a radioisotope remains from a sample that had an original mass of 4.00g. Calculate the half-life of this mystery radioisotope. How much of the radioisotope remains after 20.0 years? Show calcs and don't forget sig fig processes.

Which of the following warnings would an agricultural chemist tell a farmer who wants to recycle his or her own ammonia? recycling ammonia is a difficult process that sometimes takes weeks. recycling ammonia requires a degree in biochemistry or a related field. recycling ammonia can be harmful because it is highly flammable and toxic. recycling ammonia costs too much money considering the price of the necessary chemicals.