Solutions

• Solution


  A homogeneous mixture that contains a solute and a solvent
• Solutions can be solids, liquids and gases
• Parts of a solution

  • Solute
  • Solvent
• Solvent


  The part of the solution that does the dissolving
• Solute


  The part of the solution that is dissolved
• Soluble


  A substance that can be dissolved
• Table salt is soluble in water
• Melted wax is insoluble in water
• All gases mix with one another
• Gases dissolve better in cold liquids than hot liquids
• Miscible


  Liquids that mix together
• Immiscible


  Two liquids that don't mix
• Concentration


  The ratio of moles of solute to solvent
• Concentration is usually expressed in molarity
• Molarity equation


  Moles of solute / Volume of solution
• Determining molarity of ammonium nitrate solution

  1. Find moles of ammonium nitrate (8g / 80g/mol = 0.1 mol)

  2. Find volume of solution (2L)

  3. Molarity = moles / volume = 0.1 mol / 2L = 0.05 M
• Determining grams of calcium chloride required for 1.2 M, 250 mL solution

  1. Find moles of calcium chloride (1.2 M * 0.25 L = 0.3 mol)

  2. Find mass of calcium chloride (0.3 mol * 111 g/mol = 33.3 g)
• Determining molarity of 65 g NaOH in 500 mL solution

  1. Find moles of NaOH (65 g / 40 g/mol = 1.63 mol)

  2. Find volume of solution (0.5 L)

  3. Molarity = moles / volume = 1.63 mol / 0.5 L = 3.26 M
• Determining moles of solute for 0.05 M HCl, 2.5 L solution

  Find moles of HCl (0.05 M * 2.5 L = 0.125 mol)
• Determining volume of 16 M stock solution to make 2 M, 500 mL solution

  1. Use M1V1 = M2V2 equation

  2. (16 M)(V1) = (2 M)(500 mL)

  3. V1 = (2 M * 500 mL) / 16 M = 62.5 mL
• Types of solutions


  • Saturated
  • Unsaturated
  • Supersaturated
• Saturated solution has solute particles settled on the bottom
• Unsaturated solution can dissolve more solute
• Supersaturated solution has more solute than it can theoretically hold
• One seed crystal causes a supersaturated solution to solidify
• Saturated solution cannot dissolve more solute
• Compounds


  • SO₂
  • NH₃
  • I₂
  • HCl
• SO₂


  • Non-polar, London dispersion forces
• NH₃


  • Polar, dipole-dipole forces, H-bonding
• I₂


  • Non-polar, London dispersion forces
• HCl


  • Polar, dipole-dipole forces
• Polar compounds dissolve in polar solvents like water
• Non-polar compounds dissolve in non-polar solvents like carbon tetrachloride
• Concentration of solution


  Affects freezing point, vapor pressure, evaporation rate
• More concentrated solutions have lower freezing points
• More concentrated solutions have higher vapor pressures
• More concentrated solutions evaporate quicker
• Salts


  • CaCl₂
  • Pb(NO₃)₂
  • NaNO₃
  • NaCl
  • KCl
  • KNO₃
  • Ce₂(SO₄)₃
• KCl, NaCl, KNO₃


  • Solubility increases with temperature
• Ce₂(SO₄)₃


  • Solubility decreases with temperature