12.5.12

Identifying Gases

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Identifying Gases

Different gases are identified by unique chemical tests, like glowing/lighted splints, or solutions, revealing properties like alkalinity, combustibility, or bleaching ability.

Illustrative background for Testing for ammonia (NH<sub>3</sub>) gasIllustrative background for Testing for ammonia (NH<sub>3</sub>) gas ?? "content

Testing for ammonia (NH3) gas

  • A damp red litmus paper is used to spot ammonia gas.
    • Ammonia turns damp red litmus paper blue.
    • This happens because ammonia is an alkali gas.
Illustrative background for Testing for carbon dioxide (CO<sub>2</sub>) gasIllustrative background for Testing for carbon dioxide (CO<sub>2</sub>) gas ?? "content

Testing for carbon dioxide (CO2) gas

  • Chemistry tests carbon dioxide with limewater (calcium hydroxide).
  • Carbon dioxide makes limewater turn milky or cloudy.
    • This reaction forms calcium carbonate, a white solid.
Illustrative background for Testing for chlorine (Cl<sub>2</sub>) gasIllustrative background for Testing for chlorine (Cl<sub>2</sub>) gas ?? "content

Testing for chlorine (Cl2) gas

  • Chemistry uses damp blue or red litmus paper to identify chlorine.
  • Chlorine bleaches the colour from damp litmus paper, making it white.
Illustrative background for Testing for hydrogen (H<sub>2</sub>) gasIllustrative background for Testing for hydrogen (H<sub>2</sub>) gas ?? "content

Testing for hydrogen (H2) gas

  • Chemistry uses a lit splint to test for hydrogen.
    • Hydrogen makes a 'pop' sound when it meets a lit splint.
    • This test shows that hydrogen is flammable.
Illustrative background for Testing for oxygen (O<sub>2</sub>) and sulphur dioxide (SO<sub>2</sub>) gasesIllustrative background for Testing for oxygen (O<sub>2</sub>) and sulphur dioxide (SO<sub>2</sub>) gases ?? "content

Testing for oxygen (O2) and sulphur dioxide (SO2) gases

  • Chemistry uses a glowing splint test for oxygen. Oxygen relights the glowing splint.
  • Chemistry tests sulphur dioxide with acidified potassium manganate(VII) solution.
  • Sulphur dioxide changes purple manganate(VII) solution to colourless.

Jump to other topics

1States of Matter

2Atoms, Elements & Compounds

3Stoichometry

4Electrochemistry

5Chemical Energetics

6Chemical Reactions

7Acids, Bases & Salts

8The Periodic Table

9Metals

10Chemistry of the Environment

11Organic Chemistry

11.1Formulae, Functional Groups & Terminology

11.2Naming Organic Compounds

11.3Fuels

11.4Alkanes

11.5Alkenes

11.6Alcohols

11.7Carboxylic Acids

11.8Polymers

12Experimental Techniques & Chemical Analysis

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