How is delta G related to the equilibrium constant?
Answer
Verified
441k+ views
Hint: Thermodynamics is a branch of physical chemistry that deals with many forms of energy and heat. It tells us about how thermal energy is converted into other forms of energy. Gibbs free energy is used for the measurement of the maximum amount of work done in a thermodynamic system.
Complete step-by-step answer:Gibbs free energy is denoted with symbol G and its value is expressed in Joules.
Now let us discuss the relationship between the change in Gibbs free energy and equilibrium constant-
The change in Gibbs free energy is related to the change in standard Gibbs free energy that is represented by $\Delta {{G}^{{}^\circ }}$ .
Now let us see the equation
$\Delta G=\Delta {{G}^{{}^\circ }}+RT\ln Q$
Where, $\Delta G$ is change in Gibbs free energy
$\Delta {{G}^{{}^\circ }}$ change in standard Gibbs free energy
$R$ is the gas constant $\left( R=0.08314 kJ mol{{l}^{-1}}{{K}^{-1}} \right)$
$T$ is the temperature on Kelvin
$Q$ is the reaction quotient
At equilibrium,
$\Delta G=0$ and $Q=K$
Here, $K$ is the equilibrium constant
Therefore, on substituting the value in the above formula we get,
$\Delta {{G}^{{}^\circ }}=-RT\ln K$
As $\ln =2.303\log $
On further substituting we get,
$\Delta {{G}^{{}^\circ }}=-2.303RT\log K$
If the value of equilibrium constant is large then it will result in negative value of change in Gibbs free energy. It indicates reaction spontaneity. It is an irreversible process that can only be reversed by external agents.
Note: Change in Gibbs free energy helps in determining the extent of chemical change and direction.
If the change in Gibbs free energy is negative then it is a spontaneous reaction.
Spontaneity depends upon the temperature of the system.
Spontaneous process releases free energy and moves to a more stable energy state.
Complete step-by-step answer:Gibbs free energy is denoted with symbol G and its value is expressed in Joules.
Now let us discuss the relationship between the change in Gibbs free energy and equilibrium constant-
The change in Gibbs free energy is related to the change in standard Gibbs free energy that is represented by $\Delta {{G}^{{}^\circ }}$ .
Now let us see the equation
$\Delta G=\Delta {{G}^{{}^\circ }}+RT\ln Q$
Where, $\Delta G$ is change in Gibbs free energy
$\Delta {{G}^{{}^\circ }}$ change in standard Gibbs free energy
$R$ is the gas constant $\left( R=0.08314 kJ mol{{l}^{-1}}{{K}^{-1}} \right)$
$T$ is the temperature on Kelvin
$Q$ is the reaction quotient
At equilibrium,
$\Delta G=0$ and $Q=K$
Here, $K$ is the equilibrium constant
Therefore, on substituting the value in the above formula we get,
$\Delta {{G}^{{}^\circ }}=-RT\ln K$
As $\ln =2.303\log $
On further substituting we get,
$\Delta {{G}^{{}^\circ }}=-2.303RT\log K$
If the value of equilibrium constant is large then it will result in negative value of change in Gibbs free energy. It indicates reaction spontaneity. It is an irreversible process that can only be reversed by external agents.
Note: Change in Gibbs free energy helps in determining the extent of chemical change and direction.
If the change in Gibbs free energy is negative then it is a spontaneous reaction.
Spontaneity depends upon the temperature of the system.
Spontaneous process releases free energy and moves to a more stable energy state.
Recently Updated Pages
The correct geometry and hybridization for XeF4 are class 11 chemistry CBSE
Water softening by Clarks process uses ACalcium bicarbonate class 11 chemistry CBSE
With reference to graphite and diamond which of the class 11 chemistry CBSE
A certain household has consumed 250 units of energy class 11 physics CBSE
The lightest metal known is A beryllium B lithium C class 11 chemistry CBSE
What is the formula mass of the iodine molecule class 11 chemistry CBSE
Trending doubts
The reservoir of dam is called Govind Sagar A Jayakwadi class 11 social science CBSE
10 examples of friction in our daily life
What problem did Carter face when he reached the mummy class 11 english CBSE
Difference Between Prokaryotic Cells and Eukaryotic Cells
State and prove Bernoullis theorem class 11 physics CBSE
Proton was discovered by A Thomson B Rutherford C Chadwick class 11 chemistry CBSE