Question

Gases have lower density compared to that of solids and liquids. Explain.

Answer 1

Hint: We can describe density of the substance by the equation $Density=\dfrac{Mass}{Volume}$
The force of attraction between the molecules is the least in gases compared to solids and liquids.

Complete step by step answer:
- Density is a property of a matter which is given by its mass per a unit volume of the substance. So, we can say that $Density=\dfrac{Mass}{Volume}$
- Here, we are given to compare the density of solids, liquids and gases. In order to predict the difference between their densities, we need to understand their structures first. Let’s study them.
i) Solids: In solids, the particles are closely bound to each other and very minimal space is there in between the atoms of the solid. Thus, there is a high number of atoms present in the certain amount of volume. Thus, we can say that as in less volume, a higher amount of atoms means the mass is present. Thus, the density of the solids is the highest.
ii) Liquids: Liquids have relatively less attraction between their molecules and so, the molecules have more space between them in comparison with solids. So, we can say that there is little less amount of mass present per unit volume in liquids than solids. So, as a result, we can say that the density of the liquids is less than that of solids.
iii) In Gases, The force of attraction between the molecules of gases is the least and so they move around in the space and have very high distance between the molecules. Thus, we can say that the atoms per unit volume will be least in the gases and so their density will also be the least.
Thus, we can say that gases have lower density than that of solids and liquids.

Note: As density involves volume of the substance in the equation, we can say that with high increase in the temperature, the density of the substance will decrease and with high decrease in temperature the density will increase.