Concentration of solutions

• Concentration


  A measure of how crowded things are in a solution
• Lots of reactions in chemistry take place between substances that are dissolved in a solution
• Concentration


  The amount of a substance (e.g. the mass or the number of moles) in a certain volume of a solution
• The more solute (the substance that's dissolved) there is in a given volume

  The more concentrated the solution
• Concentration


  Can be measured in g/dm3
• Concentration examples


  • What the concentration in g/dm3 of a solution where 30g of sodium chloride is dissolved in 0.2 dm3 of water
  • What the concentration in g/dm3 of a solution with 15 g of salt dissolved in 500 cm3 of water
• Calculating concentration


  1. Convert the volume to dm3 by dividing by 1000

  2. Divide the mass of solute by the volume of solvent
• Concentration can be uncertain, so it's important to consider the range of your measurements
• Calculating concentration


  • What mass of a salt would you need to dissolve in 0.40 dm3 of water to make a solution with a concentration of 24 g/dm3
• Calculating mass of solute


  Use the formula: mass = concentration x volume