Advertisements
Advertisements
Question
Describe a simple experiment to show that l/5th of air is oxygen.
Advertisements
Solution
Aim : To show that l/5th of the air is oxygen.
apparatus required : Glass trough, bell jar, stopper, water, phos-phorus, evaporating dish
PROCEDURE
- a glass trough is filled with water
- A dry evaporating dish containing white phosphorus is made to float on the water.
- This apparatus is covered with a well stoppered bell jar with markings on its side.
- A glowing iron wire is introduced into the bell jar by opening the stopper
- The phosphorus is carefully ignited.
- Re-stopper the apparatus
- The phosphorus bums with a brilliant flame farming dense white fumes of phosphorus pentoxide.
- Soon the burning ceases and the water level starts rising.
- The water occupies approximately l/5th of the original volume, as the fumes dissolve in water.
- Some phosphorus is left unburnt in the dish. The air left behind in the bell jar does not allow the phosphorus to burn.
INFERENCE : The experiment shows that the volume of air oc-cupied by oxygen is 1 /5th.
APPEARS IN
RELATED QUESTIONS
Fill in the blank space by choosing the correct word from the given list.
List: oxygen, carbonic, suIphurUioxide gas, precipitation, helium
Solution of carbon dioxide in water is called _________ acid.
Match the statements in List 1 with the correct answers in List 2
| List 1 | List 2 | ||
| 1 | An impurity in air | A | Water vapour |
| 2 | The component of air which supports combustion | B | Respiration |
| 3 | The inert component in the air slightly soluble in water | C | Rare gases |
| 4 | The component of air which minimizes the rate of evaporation | D | Sulphur dioxide |
| 5 | The process which involves oxidation of food substance in living organisms | E | Helium |
| 6 | The component of air which finds application in observation balloons | F | Carbon dioxide |
| 7 | The process which involves oxidation of substances, liberating heat and light energy | G | Combustion |
| 8 | The component of air which is heavier than air and fairly soluble in water | H | Nitrogen |
| 9 | The process by which atmospheric carbon dioxide is absorbed by plants resulting in the formation of carbohydrates | I | Photosynthesis |
| 10 | The component of air which is lighter than air and less than 1% in air | J | Oxygen |
State four different properties of a compound and a mixture.
Write the percentage of the gases present in air.
What is the presence of harmful substance in the air called?
When air is moving with cool and soothing, it is called a cyclone.
The composition of air changes slightly from place to place. Give examples.
When cooled to -57°C, gaseous carbon-di-oxide becomes a liquid.
Mountaineers carry oxygen cylinders with them because ______.
A list of words is given in a box. Use appropriate words to fill up the blank in the following statement.
A weather cock shows the ______ in which the air is moving at that place.
