How many moles (of molecules or formula units) are in each sample? a) 1.96 kg CO2
b) 37.0 g KNO3
c) 111.9 kg Na2SO4
Express your answer to three significant figures and include the appropriate units.

Which of the following is a compound? a.carbon b.oxygen c.hydrogen d.water

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?

Asample of aluminum foil contains 8.60 × 1023 atoms. what is the mass of the foil?