Definition Of Gases
A gas has neither any shape nor any definite volume, It takes the shape of the container and occupies the whole space available.
Example of Gases: If we open a bottle of perfume, the aroma fills the whole room. If we open the door, the aroma fills the next room also.
More About Gases:
According to kinetic theory, a gas has molecules at a very large distance from each other, very much larger than in solids and liquids. So the intermolecular force of attraction diminishes to almost zero.
The motion of gas molecules is rapid. In a gas the molecules move about freely and occupy whatever space is available.
A gas has no shape or volume of its own.
In a gas there is plenty of empty space between molecules, therefore gas can be easily compressed.
Gases Worked Examples:
Which of the following character describes a gas?
A. Particles move about freely at high speed.
B. Fixed shape and volume
C. Particles vibrate and cannot change positions
D. Particles vibrate but can change positions.
Correct answer is A
Solution:
Step 1:In gases particles move about freely at high speed.
Step 2: Only solids will have fixed shape and volume.
Step 3: In solids particles vibrate and cannot change positions.
Step 4: In liquids particles can vibrate but can change positions..
Related terms: Solids | Liquids | Molecules.