Hello, I am been tinkering about chemistry and they are bunch of things I don't get. I know I am asking stupid questions; that is why I didn't ask my teacher. First of all, Why is mole 12g of carbon-12? How does the mole help us? Since everything is made out of the elements listed in the periodic table of elements, how come hydrogen and oxygen from the air doesn't turn into water? how come (H2O) as a whole has 1 mole while there are 2 mole of hydrogen? What is the difference between particles, atoms and molecules? ANY HELP WOULD BE GREATLY APPRECIATED!