Untitled

• Molarity


  One of the many ways to measure concentration or the strength of a solution
• Calculating molarity


  Moles of solute / Liters of solvent
• Molality


  An additional way to measure the strength or concentration of a solution
• Calculating molality


  Moles of solute / kg of solvent
• Molarity and molality can be very close if water is the solvent
• Solving molarity problems


  1. Identify the solute and solvent

  2. Convert solute to moles

  3. Convert solvent to liters

  4. Apply molarity formula
• Solving molality problems


  1. Identify the solute and solvent

  2. Convert solute to moles

  3. Convert solvent to kg

  4. Apply molality formula
• Molarity vs Molality


  • Molarity uses liters of solvent, molality uses kg of solvent
• Molarity problems


  • Calculate molarity of 0.40 mol solute in 1.6 L solution
  • Calculate molarity of 325 g NaCl in 750 mL solution
  • Calculate molarity of 140 g KCl in 600 mL water
  • Calculate molarity of 724.4 g ammonium phosphate in 4500 mL alcohol
  • Calculate moles of solute in 2.2 L of 3.1 M silver nitrate solution
  • Calculate mass of MgCl2 needed for 700 mL of 1.4 M solution
  • Calculate molarity of 93.2 g copper(II) sulfate in 290 mL water
• Molality problems


  • Calculate molality of 326 g C6H6 in 820 g acetone
  • 10. Calculate mass of glucose needed for 400 g ethanol to make 1.6 m solution
  • 12. Calculate mass and volume of ethanol for 360 g sucrose to make 1.6 m solution