Solubility Notes Unit 5

Solubility Definition The max amount of a solute that can dissolve in a given amount of solvent at a certain temp. Ex. NaCl at 25oC - 36g NaCl/100g H2O

Factors at affect solubility Surface area in general the smaller the substance (larger surface area) is the more quickly it dissolves - crushing large sub. increases surface area which increases solubility

Factors at affect solubility Agitation stirring or shaking helps the particles disperse making it dissolve easier.

Factors at affect solubility Temperature in general, the higher the temp. the easier it is to dissolve Increase movement of particles and cause more collisions to increase solubility

Factors at affect solubility Pressure – gases only increase P, helps gases stay in a solvent

Factors at affect solubility Types of solute/solvent - likes dissolve likes Polar – uneven charge (like ionic) Nonpolar – even charge (like covalent)

Factors at affect solubility (add this to the note sheet) Amount of solvent Increasing the solvent allows the solute more “space” to dissolve in

Solutions involving solubility Unsaturated – does not contain the max solute Saturated – contains the max solute Supersaturated – contains more than the max solute (heat it up, add more than max, allow to cool)

How do you tell what is soluble in water? Solubility chart To read the chart: 1. Find the positive (first) item across the top 2. Find the negative (second) item across the side 3. Find where they meet S = soluble = dissolved in water SS = slightly soluble – some will dissolve in water I = insoluble = does not dissolve in water – a solid will form If the block is empty the compound does not exist

Examples: It is soluble or insoluble? 1. AlBr3 2. AgC2H3O2 3. ZnSO3 4. (NH4)3PO4 5. CdCO3

Solubility Chart How many grams of KCl will dissolve in water at 90oC? At what temperature will the same amount of NH3 and NaNO3 dissolve? 3. At what temperature would 40 grams of KNO3 dissolve?