Why is hydrogen, carbon, and oxygen found in most compounds?

In the millikan oil drop experiment they determined that every drop had a charge which was a while number multiple of -1.60x10^-19. if a drop has a total charge of -9.60x10^-19 then how many excess electrons are contained within the drop?

How many grams of co(g) are there in 74.5 ml of the gas at 0.933 atm and 30o c?

Hey guys so i need to know what is _nh3+> nh4oh ~chemistry~