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ICSE Class 7 Chemistry Question 1 of 20

Air & Atmosphere — Question 3

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Question 3

Explain Lavoisier's experiment which provided evidence to the discovery of components in air.

Answer

Apparatus: The apparatus was set up as shown, with the mercury in the curved necked retort and air in the bell jar.

Explain Lavoisier's experiment which provided evidence to the discovery of components in air. Air & Atmosphere, Simplified Chemistry Dalal Solutions ICSE Class 7.

Procedure: The mercury in the retort was then heated for several days.

Observation:

  1. A red layer was formed on the heated mercury surface in the retort.
  2. The level of mercury in the trough rose by 15\dfrac{1}{5} .

Conclusions:

  1. The oxygen in the retort combined with the mercury forming mercury [II] oxide [red layer] and the level in the trough rose by 15\dfrac{1}{5} th of the original volume, thereby occupying the space of the used oxygen in the bell jar.
  2. The active part of the air removed by mercury on heating was named 'oxygen'.
  3. The remaining inactive part of the air in the bell jar was then named 'nitrogen'.