SC8c Bases and Salts Flashcards
base?
a substance that reacts with an acid to form a salt and water only
base + acid →
salt + water
neutralisation reaction?
a chemical reaction between a base and acid to form salt and water
example of bases?
metal oxides
salt?
a compound of a metal and a non metal
nickel oxide + hydrochloric acid →
nickel chloride + water
what do the following acids for as salts?
a. hydrochloric acid
b. nitric acid
c. sulfuric acid
d. ethanoic acid
a. chlorides
b. nitrates
c. sulfates
d. ethanoates
what ions are are present in hydrochloric acid?
H+ and Cl-
what ions are present in nitric acid?
H+ and NO₃⁻
what ions are present in sulfuric acid?
H+ and SO₄⁻²
what ions are present in ethanoic acid?
H+ and CH₃COO-
what do all aqueous solutions contain and what happens to them?
contain H+ ions and only these change in chemical reactions whilst the negative ions do not
what do metal oxide bases contain?
positive metal ions or ammonium ions and oxide ions
what happens to the hydrogen ions when a salt is formed? neutralisation reaction
they are replaced by metal or ammonium ions
when hydrogen ions and oxide ions react what is formed? and why? neutralisation reaction
water molecules which removes the hydrogen ions from the solution so the pH increases
iron oxide + nitric acid →
iron nitrate + water
what happens in this reaction:
copper oxide + sulfuric acid → copper sulfate + water
~copper ions have taken the place of the hydrogen ions in sulfuric acid
why is an excess base always added?
to make sure all the acid is used up
why is the excess reactant removed?
to make sure the salt made is pure so it is filtered which leave only the salt and water
why do we only want salt and water to remain?
so the solution can then be heated to remove the water so that crystallisation of the salt occurs
ESQ - explain how the pH of the acidic chimney gases will change as they pass over calcium oxide? (3 marks)
~hydrogen ions in the acid combine with oxide ions from the calcium oxide
~to form water
~pH will get higher (become more neutral)
~as hydrogen ions are removed
