Page 1 - 3-Lesson Notes-Oxygen Cycle

SAI INTERNATIONAL SCHOOL
Class - VI
Subject - Chemistry
Topic – Air Around Us
Sub-Topic – Oxygen Cycle

Lesson Notes

Activity:-
To prove that one-fifth of air is oxygen.

Materials required- Sodium hydroxide solution, a trough, a candle, a bottle, and
matchsticks.

Procedure
• The bottle is marked with five equal parts (0-5).
• Fix the candle in the trough
• Pour the sodium hydroxide solution into the trough.
• Inverted the marked bottle over it.
• Adjust the solution till the zero mark.
• Remove the bottle and light the candle.
• Now replace the bottle over it.
• Now record the observation.

Observation

The candle is extinguished after sometimes and the level of the solution rises to mark 1.

Inference

The candle is extinguished after consuming oxygen present inside As sodium hydroxide
solution rises till level 1 indicates that the space occupied by the oxygen is taken by
sodium hydroxide solution. This proves that one part out of the five parts of air is oxygen.
The remaining parts(4 parts) are nitrogen and a small amount of other gases present in
the air.

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