Chemistry NCERT Exemplar Solutions Class 11th Chapter Six

This is a Long Answer Type Questions as classified in NCERT Exemplar

We know,

ΔS_total = ΔS_sys + ΔS_surr

When a system is in thermal equilibrium with its surroundings, the surroundings' temperature is the same as the system's. Furthermore, a rise in the enthalpy of the surroundings equals a decrease in the system's enthalpy. As a result of the entropy shift in the environment,

ΔS_surr = ΔH_surr/T = -ΔH_sys/T

ΔS_total = ΔS_sys = (-ΔH_sys/T)

Rearranging the above equation:

ΔS_total = TΔS_sys - ΔH_sys

For spontaneous process,

ΔS_total > 0, so 

TΔS_sys - ΔH_sys> 0

⇒ ( - ΔH_sys - TΔS_sys) > 0

The above equation can be written as

- ΔG > 0

ΔG = ΔH - TΔS < 0

ΔH_sys is the enthalpy change of a reaction, TΔS_sys is the energy which is not available to do

useful work. As a result, G is a measure of 'free energy, ' as it is the net energy available to conduct beneficial work. As a result, it's also known as the reaction's free energy. At constant pressure and temperature, G gives a set of conditions for spontaneity,

(i) If ΔG is negative (<0), the process is spontaneous.

(ii) If ΔG is positive (>0), the process is nonspontaneous.

 Unit of ΔG is Joule.

 The reaction will be spontaneous at high temperature.

This is a Long Answer Type Questions as classified in NCERT Exemplar

A contrast is drawn in thermodynamics between extensive and intense qualities. An extensive property is one whose value is proportional to the amount or size of matter in the system. Extensive properties include mass, volume, internal energy, enthalpy, and heat capacity, to name a few.

Properties that are independent of the amount or size of matter present are known.

As though they were intensive properties Temperature, density, and pressure, for example, are intense properties. A molar property? m, is the value of an extensive property of the system for 1 mol of the substance. If n is the amount of matter? m =? /n, is independent of the amount of matter. An intensive property is always the ratio of two extensive properties.

Extensive/Extensive = Intensive

E.g., Mole Fraction = Moles / Total number of moles = Extensive/Extensive