Name the hydro carbon. I really need your help guyz

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?

The molality of calcium chloride (cacl2) in an aqueous solution is 2.46 m. what is mole fraction of the solute?

State one important difference between a physical change and a chemical change?