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I/GCSE Chemistry- Making crystals

Practicals

August 20, 2021

This I/GCSE Chemistry blog post will indicate the practical process of creating crystals from salts.

  • The method of finding out exactly how much of each solution you will need to produce one of these salts is called a titration.
  • The point at which an indicator changes colour during the titration is called the end point of the titration.
  • Having found out how much acid and alkaline is needed, you redo the test, but without the indicator.

Making sodium sulfate crystals.

  • 25cm^3 of sodium hydroxide is transferred to a conical flask using a pipette, and a few drops of methyl orange is added as indicator.
  • Dilute sulfuric acid is run in from the burette until the indicator turns orange.
  • The volume of each acid is noted, and the same amount of each are added into a conical flask without any indicator.
  • The solution can be crystallised by evaporating it to the point the crystals will form on cooling.

Making sodium chloride crystals

  • Using ammonia solution, rather than sodium, makes no different to the method used.
  • Although simple ammonium salts don’t have water of crystallisation, you would still crystallise them slowly rather than evaporating them to dryness.
  • Heating dry ammonium salts tend to break them up.   

That is all!

References:

https://www.google.com/url?sa=i&url=http%3A%2F%2Fwww.chemistryrules.me.uk%2Fmiddle%2Fnaclprep.htm&psig=AOvVaw1BPl57ziLPoxfi5OuAQ9iE&ust=1629530248408000&source=images&cd=vfe&ved=0CAsQjRxqFwoTCIigrK-Hv_ICFQAAAAAdAAAAABAD