The number of water molecules present in a drop of water (volume 0.0018^1t ml) at room temperature is (d=1g/ml) ?

To find the number of water molecules in a drop of water, we need to calculate the mass of the water and then use Avogadro's number to find the number of molecules.<br /><br />Given:<br />Volume of water = 0.0018 ml<br />Density of water (d) = 1 g/ml<br /><br />Step 1: Calculate the mass of water.<br />Mass of water = Volume of water * Density of water<br />Mass of water = 0.0018 ml * 1 g/ml<br />Mass of water = 0.0018 g<br /><br />Step 2: Calculate the number of water molecules.<br />Number of water molecules = Mass of water / Molar mass of water<br />Number of water molecules = 0.0018 g / 18.015 g/mol<br />Number of water molecules ≈ 9.89 x 10^21 molecules<br /><br />Therefore, the number of water molecules present in a drop of water at room temperature is approximately 9.89 x 10^21 molecules.