Question

1. when similar gases are mixed then, entropy of mixing explanation

Answer 1

A gas will always flow into a newly available  volume and does so because its molecules are rapidly bouncing off one another and hitting the walls of their container, readily moving into a new allowable space. It follows from the second law of thermodynamics that a process will occur in the direction towards a more probable state. In terms of entropy, this can be expressed as a system going from a state of lesser probability (less microstates) towards a state of higher probability (more microstates). This corresponds to increasing the  W  in the equation  S=kBlnW .

Answer 2

Answer:

Let's explain using an example -

F2 (g)

Cl2 (g)

Br2 (g)

All of them are gases i.e similar compounds.

• Entropy is directly proportional to molar mass.

So, more will be the molar mass, lesser will be the entropy.

In this case,

• molar mass of Flourine is least,
• molar mass of chlorine is moderate,
• molar mass of bromine is maximum.

So,

• entropy of flourine is maximum,
• entropy of chlorine is moderate.
• entropy of bromine is least.

______________________

Additional -

• we can calculate the absolute value of entropy by using third law of thermodynamics.

→ Increase in entropy ( ∆S = +ve )

→ Decrease in entropy ( ∆S = -ve)

Solid < Liquid < Gas

• Entropy is maximum of gas
• entropy is moderate of Liquid
• entropy is least of solid.