GCSE Science | Acids and Bases

What do all acids contain and what is their pH?

• H⁺ ions
• pH is closer to 1 for strong acids and closer to 6 for weak acids

What are the common ions?

• nitrate - NO₃^-
• sulfate - SO₄^2-
• carbonate - CO₃^2-
• phosphate - PO₄^3-

What are the common acids?

• HCl
• HNO₃
• H₂SO₄
• H₃PO₄

What is the difference between a strong acid and a weak acid?

• strong acids completely disocciate in water
• weak acids partially disocciate in water

What happens to [H⁺] if pH goes up by 1?

• concentration of H⁺ ions
• goes down
• by 1/10th

What happens to [H⁺] if pH goes down by 1?

• concentration of H⁺ ions
• goes up
• by x10

What is a salt?

• A salt is formed when
• the H⁺ ion in the acid is replaced by a metal ion

Acid and base reactions

• acid + metal --> salt + hydrogen
• acid + metal oxide --> salt + water
• acid + metal hydroxide --> salt + water
• acid + metal carbonate --> salt + water + carbon dioxide

Ionic equation for neutralisation

• H⁺ + OH^- --> H₂O