An undergraduate weighed out 20grams of sodium hydroxide pellets. If Na = 23, O = 16 andH = 1, What is the mole of this sodium hydroxide.

The answer would be. 5 mols because you take the total amount of grams, which is 20, and you had up the molar mass of sodium hydroxide, which would be 40. After you have this you would set this up as a stochiometry equation. With 1 mol on top you dived 20/40 to cancel out your grams. This leaves you with. 5 mols