An electrically neutral atom consists of 15 neutrons, 13 electrons, and a number of protons. What is its mass number?

A.13

B.15

C.28

D.30

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.