Molality (m) A concentration that expresses the moles of solute in 1 kg of solvent Molality (m) = moles of solute 1 kg solvent

Units of Molality 2.0 m HCl = 2.0 moles HCl 1 kg solvent

Molality Calculation NaOH is used to open stopped sinks, to treat cellulose in the making of nylon, and to remove potato peels commercially. If 4.0 g NaOH are used with 500. g of water, what is the molality (m) of the solution?

Calculating Molarity = 0.20 m NaOH 1) 4.0 g NaOH x 1 mole NaOH = 0.10 mole NaOH 40.0 g NaOH 2) 500. g x 1 kg _ = 0.500 kg water 1000 g 3. 0.10 mole NaOH = 0.20 mole NaOH 0.500 kg water 1 kg water = 0.20 m NaOH

Calculating Molarity A glucose solution is made with 2.0 kg water and 72 g glucose (C6H12O6). If glucose has a molar mass of 180. g/mole, what is the molality of the glucose solution? 1) 0.20 m 2) 5.0 m 3) 36 m

Solution A glucose solution is made with 2.0 kg water and 72 g glucose (C6H12O6). If glucose has a molar mass of 180. g/mole, what is the molality of the glucose solution? 1) 72 g x 1 mole x 1 = 0.20 m 180. g 2.0 kg

Molality & Grams & Volume What is the molality of a solution prepared by mixing 3.0 moles NaOH with sufficient solvent to make a total mass of 400 g? 1) 12 m 2) 10.7 m 3) 300 m

Solution 2) 3.0 mol x 40 g = 120 g solute 1 mol mass of solvent = 400 g total – 120 g solute = 280 g solvent m = 3.0 mol 0.280 kg m = 10.7 m