Calculate the molality of a solution formed by adding 6.80 g NH4Cl to 16.5 g of water.

Question

Ch 11 Q 12

Calculate the molality of a solution formed by adding 6.80 g NH4Cl to 16.5 g of water.

molality: ___𝑚 NH4Cl

Answer 1

Molality (m) is moles of solute per kg of solvent

Moles of solute = 6.80 g NH4Cl x 1 mol / 53.49 g = 0.127 moles

Kg of solute =16.5 g H2O x 1 kg / 1000 g = 0.0165 kg

molality = 0.127 mols / 0.0165 kg = 7.70 m