In which state of matter do molecules have the lowest kinetic energy?

Explanation:

In a solid state, molecules are held together more tightly because there exists strong intermolecular forces of attraction between the molecules. Hence, these molecules can vibrate at their mean position but they cannot slide through each other.

As a result, molecules of a solid have lowest kinetic energy.

In liquids, molecules are held by less strong intermolecular forces of attraction. Hence, they are able to slide through each other.

In gases, molecules are held by weak Vaander waal forces. Hence, They have high kinetic energy and move randomly from one place to another.

Thus, we can conclude that in solid state of matter molecules have the lowest kinetic energy.

the formula mass of a molecule or a compound is the sum of the atomic weights of the atoms in its empirical formula

(that's what i know about formula mass)