Reactions of acids Flashcards
Define acid in terms of pH
A substance with a pH of less than 7
Define acids in terms of ions
A substance which releases H⁺ ions in solution
What does (aq) stand for?
Aqueous: when something is dissolved in water. E.g. NaCl(aq) is salt water
State the three common acids and give their formulae
Hydrochloric acid, HCl(aq)
Sulphuric acid, H₂SO₄(aq)
Nitric acid, HNO₃
Which ions do the common acids form in solution?
HCl forms H⁺ and Cl⁻
H₂SO₄ forms 2H⁺ and SO₄²⁻
HNO₃ forms H⁺ and NO₃⁻
What is a neutral solution?
A solution with a pH of 7. Water is an example.
How do you measure pH?
With an indicator or pH probe.
What is a base?
A metal oxide, hydroxide or carbonate that will react with an acid. E.g. copper oxide
What is an alkali?
A soluble base. E.g. sodium hydroxide
Which ions are always present in a solution of an alkali?
OH⁻
What is a salt?
An ionic compound formed when some or all of the hydrogen from an acid is replaced by a metal. E.g. CuSO₄, copper sulphate, where copper has replaced H from H₂SO₄
What type of salts are formed by the three main acids?
Hydrochloric acid produces chlorides, e.g. potassium chloride
Sulphuric acid produces sulphates, e.g. copper sulphate
Nitric acid produces nitrates, e.g. calcium nitrate
What is a neutralisation reaction?
A reaction involving an acid that results in a neutral solution
Which ions always react together in a neutralization reactions between acids and alkalis?
H⁺ and OH⁻
How can you carry out crystallization?
Filter the solution, pour into an evaporating dish, boil off half the water and then wait for the rest to evaporate naturally.
