Chapter 4 Flashcards
Define a Acid?
A acid is a proton donor (H+ donor)
Define a Base?
A base is a proton acceptor (H+ acceptor)
Define an alkali?
An alkali is a soluble base that releases OH- ions in water
What is a Amphoteric substance?
A substance that can behave as both an acid and a base
What is an example of a Amphoteric substance?
Water
What do strong acids and strong bases both do in water?
Fully dissociate in water
What do weak acids and bases do in water?
Only partially dissociate
What do ionic equations show?
Ionic equations show only those ions that react and leave out ions that are unchanged in a reaction, the spectator ions.
Define a neutralisation reaction?
When acids and bases react to form salts and neutral solutions.
When is a salt formed?
A salt is formed when the H+ of an acid is replaced by a metal ion or NH4+
What type of salt does hydrochloric acid make?
Chloride salts
What type of salt does nitric acid make?
Nitrate salts
What type of salt does sulphuric acid make?
Sulphate salts
What is the product and observations when a acid + base reaction takes place?
Salt + Water are produced and the base dissolves/ disappears.
What is the product and observations when a acid + alkali reaction takes place?
Salt + Water are produced and no visible change unless indicator added.
What is the product and observations when an acid + carbonate reaction takes place?
Salt+ Water + Carbon dioxide are produced and effervescence is seen and the carbonate dissolves.
What is the product and observations when an acid + hydrogen carbonate reaction takes place?
Salt + Water + Carbon Dioxide are produced and effervescence is seen and the hydrogen carbonate dissolves.
What is the product and observations when an acid + ammonia react?
Ammonium salt is produced and there is no visible change unless indicator added
What is an Acid-Base titration?
A technique used to accurately measure the volume of one solution that reacts exactly with another solution.
What are the three purposes of a titration?
- Finding the concentration of a solution
- Identification of any unknown chemicals
- Finding the purity of a substance
What is a standard solution?
A solution of a known concentration
When can a titration be stopped?
When 3 concordant results are reached
What are concordant results?
Results within 0.1 cm3 of each other
Why is universal indicator not suitable for titrations?
It is not suitable for titrations because it does not give a sharp colour change.
Why is a white tile used in titration?
It is used below the conical flask to see the colour change more clearly.
Why are coloured solutions used in titration?
They are used to show the end-point of a reaction ( the indicator changes colour quickly over a very small pH range)
