Answer the following questions in about twenty words.
1. Name four major constituents of the air. Also give their volume proportions in the air ?
2. Demonstrate through a simple experiment that the air mainly contains oxygen and nitrogen in the volume ratio of 1:4 ?
3. Identify two major sources of atmospheric carbon dioxide and oxygen?
4. Mention two uses of the air?
5. Show that oxygen is a supporter of combustion?
Answers
Answer:
1. Name the major constituents of air. Also give their volume proportions in air.
...
Name of Constituents % Composition
Nitrogen gas 78.1%
Oxygen gas 20.9%
Carbon dioxide gas 0.03%
Argon 0.9%
2.The air mainly contains oxygen and nitrogen in the volume ratio of 1:4 is demonstrated by an experiment named candle and a glass jar experiment. Procedure: Place a burning candle at the center of glass container. Fill up the glass container with fine amount of water.
3. Natural sources include decomposition, ocean release and respiration. Human sources come from activities like cement production, deforestation as well as the burning of fossil fuels like coal, oil and natural gas.
4. Important Uses of Air
Sustain life and growth.
Combustion.
Maintaining Temperature.
Supplier of Energy.
Photosynthesis.
5. Activity: Take a candle and fix it on a table. The candle is lighted. The candle will continue to burn due to continuously available fresh air providing the required oxygen for combustion.
Answer:
Aim of experiment: To show that air contains nitrogen and oxygen in the ratio 4:1 by volume.
Procedure: Take a glass container and fix a candle at its center. Put some quantity of water in the container. Place an empty, dry gas jar over it. Mark five marks above water surface on the jar at equal distances shown in the figure given below.
The candle is lightened and is covered with the gas jar. After some time the candle is extinguished and the water level is raised in gas jar. The raised level in water is 1/5 of the volume of air in the gas jar.
This proves that one part of the air of the jar is a gas which supports combustion, i.e., oxygen. Hence, 1/5 by volume is oxygen in air.
Explanation: