One ________ of a substance is equal to its atomic or molecular mass expressed in __________ and contains $$6.023 \times 10^{23}$$ chemical particles, which is known as ______________ of particles. Since 1 mole of any chemical substance contains same number __________ as 1 mole of any other chemical substance, we can calculate the weight of one chemical that will react with a given weight of other by using their _________ in other calculations.