Acids and Bases
A mindmap for unit 10 of the CIE IGCSE Chemistry specification, 'Acids and Bases'.
- Created by: steph
- Created on: 22-03-13 20:02
View mindmap
- Acids and Bases
- Hydrogen and hydroxide ions
- All acids form H+ ions when dissolved in water
- The pH scale
- Acids have a pH below 7
- Lower pH = more hydrogen ions
- Alkalis have a pH above 7
- Higher pH = more hydroxide ions
- pH can be measured with universal indicator paper
- Mixture of indicators showing a range of colours depending on pH
- Acids have a pH below 7
- Properties of acids
- Turns blue litmus red
- React with metals to form a salt and hydrogen
- Salt = compound formed when metal or ammonium group replaces hydrogen in acid
- React with metal oxides and hydroxides to form a salt and water
- React with carbonates (and hydrogencarbonates) to form a salt, water and carbon dioxide
- Bases
- Substances that can react with acids
- Oxides, hydroxides or carbonates of metals
- Alkalis are bases that are soluble in water
- Metal carbonates react with acids to form a salt, water and carbon dioxide
- Metal oxides and hydroxides react with acids to form a salt and water
- When base reacts with acid and salt forms: neutralisation
- Alkalis react with ammonium salts to form a metal salt, ammonia and water
- Soil acidity
- Excess acidity can be removed with bases
- Products used to remove acidity e.g. (Calcium carbonate) have neutral products
- Acids, bases and protons
- Hydrogen ion = just a proton
- Acid = proton donor
- Gives a proton to a base
- Base = proton acceptor
- Removes protons from an acid
- Strong and weak acids
- Strong: completely ionise when dissolved in water
- Good electrical conductivity, faster reaction time
- Weak: partly ionise when dissolved in water
- Strong acid has lower pH than weak acid of same conc.
- Strong: completely ionise when dissolved in water
- Strong and weak bases
- Hydroxides of alkali metals are strong bases
- Completely ionised in water
- Weak bases have lower electrical conductivity, lower pH, slower reaction rate
- Hydroxides of alkali metals are strong bases
- Oxides
- Basic oxides
- Most metal oxides
- React with acids to form salt and water
- They do not react with alkalis
- Acidic oxides
- Most non-metal oxides
- React with alkalis to form salt and water, and water to form acidic solutions
- Some react with bases when heated
- Neutral oxides
- No reaction with acids or bases
- 'Lower' non-metal oxides e.g. CO (CO2 is acidic)
- Amphoteric oxides
- Acidic and basic properties
- React with acids to form salts, react with alkalis to form complex salts
- Basic oxides
- Hydrogen and hydroxide ions
Comments
No comments have yet been made