Question

Kinetic energy of molecules is highest in:
A) Gases.
B) Solids.
C) Liquids.
D) Solutions.

Answer 1

Hint: Kinetic energy is a form of energy that a particle or an object possesses during its motion. Kinetic energy of a particle or of an object only depends on its mass and velocity. So every particle in motion has kinetic energy. Kinetic energy of particles decides the temperature of the medium.

Complete solution:
The kinetic energy of molecules is highest in gases because molecules in gases have more space between them and they observe the less intermolecular force on each other and move with higher velocity and due to higher velocity in the process higher energy.
In gases the particles move in every direction rapidly and frequently colliding with each other and the side of the container.the particles gain kinetic energy and move rapidly with an increase in temperature, the kinetic energy decreases due decrease in temperature.
Solids are compact material with closely packed molecules and its molecule exerts higher intermolecular force and that's why molecules in solids again have less velocity and have less kinetic energy.
Molecules in solution and water loosely packed but not as much as in gases because in solution and water there are many intramolecular forces.
Finally we conclude that molecules of gas have the highest kinetic energy.

So the correct option is option A.

Note:The kinetic energy of molecules in any medium also depends on Absolute Temperature. If the temperature is reduced to absolute zero then it will cease motion of molecules in medium like gas and liquid.