The following links offer some useful revision to support your learning:
BBC Bitesize – Acids and Bases
BBC Bitesize Video – Acids and Bases
BBC Bitesize Test – Acids and Bases
Miss Adams Video Lesson – Acids and Bases
To help with your learning, you may also wish to try some of the following resources:
BBC Teach Video – How Acids and Alkalis Affect Us
Making a Soluble Salt from an Insoluble Metal carbonate and an Acid
Within the National 5 Chemistry course, you will need to know:
pH
- The pH scale is an indication of the hydrogen ion concentration and runs from below 0 to above 14.
- A neutral solution has equal concentrations of H+ (aq) and OHˉ(aq) ions.
- Water is neutral as it dissociates according to the equation + – H O( ) H (aq) OH (aq) 2 producing equal concentrations of hydrogen and hydroxide ions.
- At any time, only a few water molecules are dissociated into free ions.
- The symbol indicates that a reaction is reversible and occurs in both directions.
- Acidic solutions have a higher concentration of H+ (aq) ions than OHˉ(aq) and have a pH below 7.
- Alkaline solutions have a higher concentration of OHˉ(aq) ions than H+ (aq) ions and have a pH above 7.
- Dilution of an acidic solution with water will decrease the concentration of H+ (aq) and the pH will increase towards 7.
- Dilution of an alkaline solution with water will decrease the concentration of OHˉ(aq) and the pH will decrease towards 7.
- Soluble non-metal oxides dissolve in water forming acidic solutions.
- Soluble metal oxides dissolve in water to form alkaline solutions: metal oxide + water metal hydroxide Metal oxides, metal hydroxides, metal carbonates and ammonia neutralise acids and are called bases.
- Those bases that dissolve in water form alkaline solutions.
