Unit 4: Solutions & Solubility

Unit 4: Solutions & Solubility

1. Solution

   • Definition
     • a homogeneous mixture of two or more substances made of a solute dissolved in a solvent
   • Types
     • Gas – Gas Gas – Liquid Liquid – Liquid Solid – Liquid Solid – Solid (alloys)
   • Concentration
     • the ratio of the quantity of solute or solvent
     • Concentrated
       • a large quantity of solute dissolved per unit volume
     • Dilute
       • a small quantity of solute dissolved per unit volume
     • Saturated
       • a solution where no more solute can be dissolved
     • Unsaturated
       • more solute dissolves
     • Supersaturated
       • added crystals grow
   • Dissolving Process
     • Hydration: the process of water molecules surrounding ions.  Dissociation: the separation of ions from an ionic compound as it dissolves in water.

2. Consentration

   • C=n/V
     • Molarity = number of moles of solute / volume of solution in L
   • %=solute/solution*100
     • solute is solid, solvent is liquid: %W/V both the solute and solvent are liquids: %V/V mixtures of solids in either liquids or other solids: %W/W v in mL m in g
   • ppm
     • parts per million: solute/solution*10^6

3. Solubility

   • Immiscible
     • unable to form solutions
   • Miscible
     • able to form solutions
   • Surfactants
     • substances that encourage oil and water to mix have a hydrophobic and a hydrophilic part break down hydrogen bonds to reduce surface tension
   • Related Factors
     • Nature Polarity Temperature Pressure
     • Thermal Pollution
     • Pressure
   • Solubility Curve
     • a graph showing the solubility of a substance in 100g water over a range of temperatures Point on the curve = saturated Point below the curve = unsaturated Point above the curve = supersaturation

4. Dilusion

   • the process of reducing the concentration of a solution by adding more solvent
   • C1V1===C2V2

5. Solubility Rules

   • Solubility Chart

6. Total Ionic Equation

   • a chemical equation where all soluble ionic compounds are written as dissociated ions must still be balanced Write the balanced chemical equation with states for the reaction.Write the total ionic equation by showing all of the soluble compounds as ions.Cancel spectator ions.Write the net ionic equation.
   • Stoichiometry

7. Aicds and Bases

   • Arrhenius Theory
     • Acids make H+ in water  Bases make OH- in water
   • Bronsted-Lowry Acids and Bases
     • Bronsted –Lowry acid is any compound which can donate a proton (H+).  Bronsted – Lowry base is a compound that accepts a proton
   • pH
     • a measure of the hydrogen ion concentration of a solution  High concentration of hydrogen ions means low pH Low concentration of hydrogen ions means high pH A difference of one pH unit is a ten fold difference in H+ ion concentration
     • Caulculations
       • pH= - log[H+] acid concentration: [H+] = 10^-pH
   • Titration
     • a procedure used to determine the concentration of a solution or the volume required for neutralization
     • Equivalence Point
       • the point when neutralization is complete (moles of acid = moles of base)
     • Endpoint
       • the point when a sudden, observable change occurs (usually when the indicator changes colour)