1. Understand Molality
Molality (m) is a measure of concentration defined as the moles of solute per kilogram of solvent.
2. Calculate Moles of NaCl
* Find the molar mass of NaCl: Na (22.99 g/mol) + Cl (35.45 g/mol) = 58.44 g/mol
* Divide the mass of NaCl by its molar mass: 0.630 g / 58.44 g/mol = 0.0108 mol NaCl
3. Convert Solvent Mass to Kilograms
* Divide the mass of water by 1000: 525 g / 1000 g/kg = 0.525 kg
4. Calculate Molality
* Divide the moles of NaCl by the kilograms of water: 0.0108 mol / 0.525 kg = 0.0206 mol/kg
Therefore, the molality of the NaCl solution is 0.0206 mol/kg.
