Water

• Potable water


  Safe to drink
• Pure water

  Contains no dissolved solids such as salts, has a pH of 7 (neutral)
• Potable water


  Often contains dissolved solids, pH may not be 7
• Analyzing a sample of water for purity


  1. Check pH using universal indicator paper

  2. Weigh empty evaporating basin

  3. Fill basin with water sample, heat to evaporate water

  4. Weigh basin again, if mass increased then water contained dissolved solids
• Water may still contain dissolved gases even if it doesn't contain dissolved solids
• Purifying water by distillation

  1. Heat water sample in conical flask

  2. Water vapor travels through delivery tube

  3. Vapor condenses in cold test tube, forming distilled water
• Distilled water


  Contains no dissolved solids, has a pH of 7 (pure water)