What is an organic compound called that is used to store energy and form?

We just started a new lesson in chemistry and everyone hates it and i dont get it one bit. i hate school. h el p.balanced equationc3h8+5o2-> 3co2+4h2o1.) if you start with 14.8g of propane(c3h8) and 3.44g of oxygen, which is the limiting reactant -check my answer 2.)what mass of excess reagent is left over? 3.)what mass of carbon dioxide can be made? 4.)what mass of water is produced?

How many moles of magnesium is 3.01 x10^22 atoms of magnesium?

Air can be considered a mixture. which statement does not explain why?