Gas Preparation and Gas Tests
Key Concepts
- Gases can be produced in the school laboratory when:
⚛ a compound is heated and undergoes thermal decomposition
⚛ electricity is used to decompose a compound (electrolytic decomposition)
⚛ a substance reacts with water or an acid in a displacement reaction
⚛ a substance undergoes combustion in air
- The table below summarises tests for the following gases commonly prepared in the school laboratory:
⚛ oxygen gas, O2(g)
⚛ hydrogen gas, H2(g)
⚛ carbon dioxide gas, CO2(g)
⚛ nitrogen dioxide gas, NO2(g)
⚛ sulfur dioxide gas, SO2(g)
⚛ hydrogen sulfide gas, H2S(g)
⚛ chlorine gas, Cl2(g)