Question

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

Answer 1

In the given question we will discuss the kinetic energy of molecules. So to figure out which molecule will have the highest kinetic energy we will consider the Kinetic molecular theory of matter. We will also consider various forces acting on molecules.

Complete answer:
We can easily conclude that the kinetic energy of molecules is highest in gases. Some factors are acting on it. First, we will compare the state of matter based on intermolecular forces acting on the molecules.
Let’s take the first option (A) gases. When we consider gases we know that the actual volume of molecules is negligible as compared to the total empty spaces occupied by the molecules of gas. The molecules of gases have no force of attraction between them.
The molecules are always in a state of rapid random motion in all directions. They travel in a straight line and on colliding with other molecules or with the walls of the container. Due to the random motion and collision, the velocity of gas molecules is very high and as a result, the kinetic energy of molecules is highest in gases.
When we discuss option (B) solid. They possess the maximum intermolecular attraction of molecules which leads to the lowest kinetic energy of molecules.
When we discuss option (C) liquids. They possess intermediate intermolecular attraction between solids and gases.
When we discuss option (D) solutions. The solution is formed when a solute is added to the solvent. So intermolecular attraction is similar to liquids.

Therefore, we can conclude that the Kinetic energy of molecules is highest in gases.
The correct option is (A).

Note:
The average Kinetic energy of the molecules is directly proportional to the absolute temperature $\left( T \right)$ of the system.
$\Rightarrow K\alpha T$
We can also conclude that with the increase of temperature, the average kinetic energy of gas molecules increases.