Unit 3b- Acids and Alkalis Flashcards
What type of salt does hydrochloric acid make?
Chlorides
What type of salt does sulphuric acid make?
Sulphates
What type of salt does nitric acid make?
Nitrates
How do you make chloride salts?
React with hydrochloric acid
How do you make sulphate salts?
React with sulphuric acid
How do you make nitrate salts?
React with nitric acid
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
Name HCl(aq),
Hydrochloric acid
Name H₂SO₄(aq)
Sulphuric acid,
Name, HNO₃
Nitric acid,
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⁻
Name OH⁻
Hydroxide ion
What is a salt?
An ionic substance
What type of salts are formed by the three main acids?
Hydrochloric acid produces chlorides,
sulphuric acid produces sulphates,
nitric acid produces nitrates
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⁻
Write the equation showing the reaction between H⁺ and OH⁻ ions
H⁺ + OH⁻ → H₂O
metal + acid →
→ salt + hydrogen gas
metal hydroxide + acid →
→ salt + water
metal oxide + acid →
→ salt + water
metal carbonate + acid →
→ salt + water + carbon dioxide
How do you make a soluble salt from an acid?
React the acid with a base. E.g. to make copper sulphate react copper oxide with sulphuric acid
If a salt is in solution, how do you extract it as a solid?
Allow the water to evaporate off and it will leave the salt behind as a solid.
What is a strong acid?
An acid which completely splits up into its ions in water. E.g. when HCl is in water all the HCl molecules split up into H⁺ and Cl⁻
What is a weak acid?
An acid which will have some molecules which do not split up into their ions. E.g. in ethanoic acid only some of the molecules will have split up into the ethanoate ion and H⁺ ions.
What is the relationship between the strength of an acid and its pH?
As an acid increases in strength the pH decreases.
What is a concentrated acid?
An acid where there are lots of acid particles in the water.
What is a dilute acid?
An acid where there are fewer acid particles in the water.
How is pH measured?
pH is related to the concentration of H⁺ in a solution.
What is the test for hydrogen?
Give a squeaky pop with a lit splint
What is the test for carbon dioxide?
Limewater turns from clear to cloudy
