Making a Salt from a Carbonate or Oxide
This section covers the process of creating a pure, dry sample of a soluble salt from an insoluble carbonate or oxide. The practical demonstrates the reactions between acids and metal oxides or carbonates to form salts.
Definition: A salt is an ionic substance formed from the reaction between an acid and a base.
The guide explains two main reactions:
- Acid + metal oxide → metal salt + water
- Acid + metal carbonate → metal salt + water + carbon dioxide
Highlight: Different acids produce different types of salts: hydrochloric acid makes metal chlorides, sulfuric acid makes metal sulfates, and nitric acid makes metal nitrates.
The apparatus setup is described for both carbonate and metal oxide reactions, including the use of a thistle funnel, delivery tube, and test tubes. The guide emphasizes the importance of heating the solution to ensure complete reaction and filtering to remove excess reactants.
Example: To show that carbon dioxide is produced in the carbonate reaction, limewater (calcium hydroxide) can be used as an indicator.
Potential exam questions are listed, covering topics such as crystallization methods, the purpose of heating and filtering, safety precautions, pH testing, and salt identification.
