7.3 Preparation of salts (1) Flashcards
(21 cards)
What is formed when a metal or ammonium ion replaces the hydrogen ions in an acid?
A salt is formed
This defines the general reaction of acids with metals or ammonium ions.
What type of salt does hydrochloric acid form?
Chloride
This is applicable for metal ions reacting with hydrochloric acid.
What type of salt does sulfuric acid form?
Sulfate
This is applicable for metal ions reacting with sulfuric acid.
What type of salt does nitric acid form?
Nitrate
This is applicable for metal ions reacting with nitric acid.
What is a soluble salt prepared from?
An acid and an insoluble reactant
Common insoluble reactants include metal oxides and metal hydroxides.
What products are formed when an acid and an alkali react?
A soluble salt and water
This is a neutralization reaction.
What is the purpose of titration in preparing soluble salts?
To determine known volumes of acid and alkali needed for neutralisation
This ensures the correct proportions are used.
What is the first step in separating a soluble salt from a solution?
Evaporate the water by heating the solution gently
This process leads to the formation of salt crystals.
How can a soluble salt be prepared using excess metal?
Add dilute acid to a beaker, heat, and gradually add the insoluble reactant until in excess
The excess ensures complete reaction of the acid.
List examples of insoluble reactants that can be used to prepare soluble salts.
- Excess metal
- Excess insoluble base (metal oxides and metal hydroxides)
- Excess insoluble carbonate
These reactants do not dissolve in the acid.
What are the general solubility rules for salts regarding sodium, potassium, and ammonium salts?
Soluble
These cations always form soluble salts.
Are nitrates soluble or insoluble?
Soluble
All nitrates are soluble in water.
Are chlorides soluble or insoluble?
Soluble, excluding lead and silver chloride
Most chlorides dissolve in water except for these exceptions.
Are sulfates soluble or insoluble?
Soluble, excluding barium, calcium, and lead sulfate
This highlights the exceptions to sulfate solubility.
Are carbonates soluble or insoluble?
Insoluble, excluding sodium, potassium, and ammonium carbonate
Most carbonates do not dissolve in water.
Are hydroxides soluble or insoluble?
Insoluble, excluding sodium, potassium, and ammonium hydroxide; calcium hydroxide is partially soluble
This indicates the behavior of hydroxides in water.
Define a hydrated substance.
A substance that is chemically combined with water
Example: Hydrated copper (II) sulfate.
Define an anhydrous substance.
A substance that does not contain water
Example: Anhydrous copper (II) sulfate.
What method is used to prepare insoluble salts?
Precipitation reaction
This involves combining two soluble salts to form an insoluble precipitate.
What is water of crystallisation?
Water molecules that are present in hydrated crystals
Indicated in formulas, e.g., CuSO4•5H2O.
How many molecules of water of crystallisation are in CoCl2•6H2O?
6
This indicates the specific number of water molecules associated with the compound.
