To determine the number of water molecules (H2O) in 9 grams of water, we need to follow these steps:
Calculate the molar mass of water (H2O). Molar mass of H2O = (2 * atomic mass of hydrogen) + atomic mass of oxygen = (2 * 1) + 16 = 18 grams/mol
Convert the given mass of water (9 grams) into moles. Moles of water = (mass of water) / (molar mass of water) = 9 grams / 18 grams/mol = 0.5 moles
Use Avogadro's number to determine the number of water molecules. Number of water molecules = (moles of water) * (Avogadro's number) = 0.5 * (6.02×10^23 molecules/mol) = 3.01×10^23 water molecules
Therefore, there are approximately 3.01×10^23 water molecules (H2O) in 9 grams of water.