Question

(a) A solution is made by dissolving 3.00 mole of CaClas) in enough water to make solution. The density of the solution is 1.25 g ml? 4) Calculate the molality of the solution (not the molarity!) ugh water to make 2.00 L of [3 marks]

Answer 1

The tetm Molality is uced to desckibe the concentration of a solution (molal cantenttation). TMlolahity forun ula can be caleulated by ucing the NO of solute(n) moles Molality(m) mass of colvent n k (M) we have 3maole of S solution 2.00L volume - 2x103 mL nsity ot colutiom 1:256 mL De Mass bensity volume Mass 1025 2xt03mL Morss of solutHom = 2500 of entite solution Now we hava the wags tomphises of the Solute and the solvent . which tote the masles of both

4m ordah to c aleutate molauty only need tha wass of rolvent wliah can be calenlatid bia Mats of colute tMacco of Mass colution Lolvemt SMaes Macsof solution) af solvemt Mass of colub) To caleulate mass f colute (lach) twe Use the formula Givem ma ss NO.04mmaoles Molae mas molate mass af Ca t molak waes A uolah 2Xwass of cl 40 t 2X3S. I11 Now, equat ton Given mags 3.00 mol M&/wat ma ttof solut Given wais ote 339

Sube titutu the value ot equation and quaton 2500-363 of colvent Mass 2167 of Lolvent Man 2.167 K Mas of solvent Now, we hawe evetuy insle data Hequlked to cal culate Molality Molalityn) Noof moles of colul of solvent wn K Mass 3 00 mal 2.167 K 1.384 mol KE