Calculate the exact number of water molecules present in a single drop of water weighing exactly at — Mole Concept and Some Basic Concepts of Chemistry Chemistry Question

💡 Solution & Explanation

Step 1: Find the number of moles of water in the drop. Moles $n = \frac{\text{Given Mass}}{\text{Molar Mass}} = \frac{0.018\text{ g}}{18\text{ g mol}^{-1}} = 0.001\text{ moles} = 10^{-3}\text{ moles}$. Step 2: Multiply by Avogadro's number to find molecules. Molecules $= 10^{-3} \times 6.022 \times 10^{23} = 6.022 \times 10^{20}$ molecules.