Lesson 4-5: Acids, pH scale, neutralisation Flashcards
What does HNO₃ split into when in solution?
- H⁺
- NO₃⁻
What does HCl split into when in solution?
- H⁺
- Cl⁻
What does H₂SO₄ split into when in solution?
- 2H⁺
- SO₄²⁻
What is an acid?
An acid is a substance with a pH less than 7 that can be dissolved in water to form H⁺ ions.
What is a base?
A base is a substance that reacts with an acid to neutralise it and produces a salt and water .
What 2 substances are bases?
- Insoluble metal hydroxides
- Insoluble metal oxides
Give an example of an alkali.
- Soluble metal hydroxide
What does the salt produced in a reaction between an acid and base or alakli depend on?
- The acid used
- The positive ions in the base, alkali, carbonate.
What is neutralisation?
- A chemical reaction in which an acid reacts with an alkali or a base to form salt and water.
What two things can we use to show the pH of a solution?
- pH probe
- Universal indicator
What is meant by pH?
- The concentration of hydrogen ions in a solution.
What ions does water split into?
H⁺ OH⁻
What is the pH scale?
The pH scale is the measure of acidity or alkaninity of a solution from 0 to 14.
Give the ionic equation for neutralisation.
H⁺ (aq) + OH⁻ (aq) –> H₂O (l)
What are strong acids?
- Strong acids are ones that completely ionise in aqueous solutions.
Give 3 examples of strong acids.
- Hydrochloric
- Nitric
- Sulphuric
What is the difference between concentration and strength of an acid?
- Concentration is the amount of acid (particles) in a solution.
WHEREAS
Strength is the degree of ionisation of hydrogen ions in aqueous solutions.
What is a weak acid?
A weak acid is one that is only partially ionised in aqueous solution.
Give 3 examples of weak acids.
- Ethanoic acid
- Citric acid
- Carbonic acid
What happens to the hydrogen ion concentration as the pH increases by one unit?
- The hydrogen ion concentration will decrease by factor of 10.
What is a base?
- A base is a substance that will react with an acid to neutralise it and form a salt and water.
What is the general equation for an acid + metal carbonate?
Salt + water + carbon dioxide