Molar mass

Molar mass is the weight of one mole of a substance, measured in grams. A mole is a way to count large numbers of small particles like atoms, molecules, or ions—specifically, approximately 6.022 x 10²³ particles. The molar mass tells us how heavy one mole of these particles is. For example, the molar mass of water (H₂O) is about 18 grams, meaning one mole of water weighs 18 grams. Molar mass helps chemists relate amounts of substances to their weights, enabling precise calculations in reactions and laboratory work.