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Solutions. Chemistry 111/112. Solution Formation. Solutions are homogeneous mixtures that may be solid, liquid or gaseous The composition of the solvent and solute determine whether a substance will dissolve Temperature Stirring Surface area. Saturation.
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Solutions Chemistry 111/112
Solution Formation • Solutions are homogeneous mixtures that may be solid, liquid or gaseous • The composition of the solvent and solute determine whether a substance will dissolve • Temperature • Stirring • Surface area
Saturation • Water molecules are in continuous motion • As ions from a solute solvate, they dissolve into the solvent • In a saturated solution, ions are solvating and at the same time, ions are crystallizing • A state of dynamic equilibrium occurs • This will continue unless the temperature changes • A saturated solution contains the maximum amount of solute for a given quantity of solvent at a constant temperature
Solubility The amount of solute that dissolves in a given quantity of solvent at a specific temperature and pressure to produce a saturated solution Expressed in g of solute/100g of solvent A solution that has not reached maximum solubility is called unsaturated Miscible = dissolves Immiscible = does not dissolve
Concentrations of Solutions The concentration of a solution is a measure of the amount of solute that is dissolved in a given quantity of solvent Dilute solutions contain a small amount of solute Concentrated solutions contain a large amount of solute
Molarity The number of moles of solute (mol) dissolved in one litre of solution It is also known as molar concentration Take note that it is the volume of solution, not solvent used in the expression
Making Solutions Diluting a solution involves adding solvent to a solution The amount of moles does not change but the relative strength of solute compared to solvent does M1 x V1 = M2 x V2
Percent Solutions The concentration of a solution in percent can be expressed in two ways: as the ratio of the volume of the solute to the volume of the solution or as the ratio of the mass of the solute to the mass of the solution Percent (by volume) (%v/v) = volume of solute x 100% volume of solution Percent(by mass) (%m/m) = mass of solute x 100% mass of solution