CO2, NH3, O2, CH4 - which of these is not a great choice to collect over water? Explain

Plz choose one of the compounds from the table and explain how you know the numbers of atoms in your formula. is it possible for two different compounds to be made from the exact same two elements? why or why not? with a limited number of elements (less than 120 are known), does this mean we also have a small number of compounds or do we have a large number of compounds in this world?

What is the number of moles of chemical units represented by 9.03x10^24? and how do i show work? (dumb it down )

Which part of earth’s surface receives the most direct rays from the sun? a) equator b) ocean c) poles d) mountains