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प्रश्न
When an incense stick (agarbatti) is lighted in one corner of a room, its fragrance quickly spreads in the entire room. Name the process involved in this.
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उत्तर
Diffusion is the process by which the smell of a lighted incense stick spreads in the entire room.
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संबंधित प्रश्न
The mass per unit volume of a substance is called density.
(density = mass/volume).
Arrange the following in order of increasing density-
air, exhaust from chimneys, honey, water, chalk, cotton and iron.
Arrange the following substances in increasing order of forces of attraction between particles -
water, sugar, oxygen
Name two gases which are supplied in compressed form in homes and hospitals.
Fill in the following blank with suitable words :
At room temperature, the forces of attraction between the particles of solid substances are ....................... then those which exist in the gaseous state.
Explain why, diffusion occurs more quickly in a gas than in a liquid.
Look at the diagram on the right side. Jar A contains a red-brown gas whereas jar B contains a colourless gas. The two gas jars are separated by a galas plate placed between them
- What will happen when the glass plate between the two jars is pulled away?
- What name is given to the phenomenon which takes place?
- Name the brown gas which could be in jar A.
- Which is the colourless gas most likely to be present in jar B?
- Name one coloured solid and one colourless liquid which can show the same phenomenon.

A student placed a gas jar containing air in the upside down position over a gas jar full of red-brown bromine vapours. He observed that the red-brown colour spread upwards into the jar containing air. Based on this observation, the student concluded that it is only the bromine vapour which moves up and diffuses into air in the upper jar, the air from the upper jar does not move down by diffusion into the lower jar containing bromine vapours. Do you agree with this conclusion of the student? Give reason for your answer.
Why do gases not have fixed shape?
2 litre He gas at 2 atm and 300 K is inserted into a 4 litre rigid container containing N2 at 600 K and 4 atm. Finally mixture is maintained at 600 K temperature. The final pressure of gaseous mixture would be ______ torr.
A gaseous mixture of He and O2 is found to have a density of 0.518 gL-1 at 25° C and 720 torr. The mass percent of helium in this mixture is ______.
