2: Atoms and reactions - acids and bases Flashcards
List examples of some strong and weak acids
Strong:
- hydrochloric acid HCl
- nitric acid HNO3
- sulfuric acid H2SO4
Weak:
- phosphoric acid H3PO4
- ethanoic acid CH3COOH
Which ion is responsible for acid reactions?
H+
What happens when an acid is added to water?
The acid releases H+ ions into solution.
What is the difference between strong and weak acids?
Strong acids fully dissociate whereas weak acids only partially dissociate.
List some examples of bases
- metal oxides, MgO, CuO
- metal hydroxides, NaOH, Mg(OH)2
- ammonia, NH3
- amines, CH3NH2
What is the difference between a base and an alkali?
A base is anything that reacts with an acid to form water and a salt. An alkali is any base that is soluble in water. Both neutralise acids.
List some examples of alkalis
- sodium hydroxide, NaOH
- potassium hydroxide, KOH
- ammonia, NH3
How do alkalis neutralise acids when in solution?
In solution, the OH- ions released from the alkalis when dissolved in water neutralise the H+ ions from acids, forming water.
Why is ammonia a weak base?
Only a small proportion of the dissolved NH3 reacts with water
What is meant by amphoteric?
Substances that are amphoteric can behave as acids and bases, eg glycine
What is a salt?
A salt is an ionic compound which consists of a positive ion (usually a metal ion or an ammonium ion) and a negative ion (derived from an acid).
The formula is the same as the acid, but the H+ ion has been replaced by the positive ion, eg HCl forms chloride salts.
How are salts formed?
Salts can be produced by neutralising acids with bases.
What is the ionic equation for neutralisation?
H+ (aq) + OH- (aq) -> H2O (l)
What is produced by each of these reactions?
- acid + carbonate ->
- acid + metal oxide ->
- acid + alkali ->
- acid + metal ->
- -> salt + carbon dioxide + water
- -> salt + water
- -> salt + water
- -> salt + hydrogen
