4NA - Salts Flashcards
what method is used to prepare SPA and other Group I salts?
titration
what method is used to prepare insoluble salts?
precipitation
what are the steps to obtain pure, dry crystals from a salt solution?
heat solution till saturation cool to form crystals filter to obtain crystals wash crystals with small volume of cold, distilled water dry crystals with filter paper
why must be insoluble metal/base/carbonate be added in excess in the acid + excess insoluble reagent method of preparing soluble salts?
to use up all the acid.
[This ensures the aqueous salt can easily filtered out. If excess acid was present, the aqueous salt would be contaminated by the acid.]
why must a titration be carried out twice - once with indicator, once without - in order to prepare a salt?
the first titration, with the indicator, is to determine the volumes of acid and alkali required.
the second titration, without the indicator, is to ensure the salt formed is pure and not contaiminated with indicator.
all sulfates are soluble except ______________.
barium sulfate
calcium sulfate
lead(II) sulfate
all chloride are soluble except ______________.
lead(II) chloride
silver chloride
all ammonium salts are soluble. true or false?
true
what method is used to prepare magnesium nitrate?
acid + excess insoluble metal/base/carbonate
what are some suitable reactants to prepare lithium sulfate?
Lithium hydroxide or lithium carbonate
Dilute nitric acid
[SPA + Group I salts are prepared by titration. Reagents for titration are acid + alkali or acid + soluble carbonate]
what are some suitable reactants to prepare barium sulfate?
barium nitrate or barium chloride
sodium sulfate or sulfuric acid
[barium sulfate is an insoluble salt and is prepared by precipitation. aqueous reagents are used in precipitation.]
What acid can be used to make a chloride salt?
dilute hydrochloric acid
What acid can be used to make a nitrate salt?
dilute nitric acid
what alkali can be used to make potassium chloride?
potassium hydroxide
why cant copper or silver or gold be used in the acid + excess insoluble reagent method?
copper, silver and gold are unreactive to acids.
