A car engine fueled by gasoline uses which kind of energy?

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?

Why do cells appear different in distilled water than they do in 10% salt water?

What is the indicator of the number of ions in solution? the amount of conductivity the amount of precipitate the amount of solute added