How many molecule are present in 18 gm of water?

To find the number of molecules in 18 grams of water (H₂O), we first determine the number of moles. The molar mass of water is approximately 18 g/mol. Therefore, 18 grams of water corresponds to 1 mole. Since one mole contains Avogadro's number of molecules, which is about (6.022 \times 10^{23}), there are approximately (6.022 \times 10^{23}) molecules in 18 grams of water.