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6. How would you carry out an experiment to compare hardness of water samples?

  • Add 100 cm3 of sample water to a conical flask. Taste it and record the flavour.
  • Add 100cm3 of sample water to a conical flask. Under a microscope cound the number of ions present and record their number.
  • Add 100 cm3 of sample water to a conical flask. Add 1cm3 soap solution to the water, put a bung in and shake. Repeat until a good lasting leather is formed ( bubbles cover the surface for atleast 30 seconds). Record how much soap was used.
  • Add 100cm3 of sample water to a conical flask. Boil the water to 105 degrees celcius. Let it evapourate. Measure the amount of limescale produced.

7. What gives water it's characteristic taste?

  • The vapours in the clouds
  • The ions dissolved in it
  • The flavourings added
  • The bottle it's packaged in

8. What kind of hardness will be removed with the use of sodium cabonate (Na2CO3) ?

  • Temporary and Permanent
  • Temporary
  • Permanent