Consider the reaction:
Given that
Interpretation:
The standard free energy change for the formation of
Concept introduction:
All the energy available in the system that is utilized in doing useful work is called Gibbs free energy.
The standard free energy change is the change in free energy that occurs under the standard state condition.
The standard free energy of formation is defined as the free energy change that occurs when one mole of a compound is combined from its constituent elements with each in the standard state.
Answer to Problem 85AP
Solution:
a)
b)
c)
d)
Lightening helps in the production of better crops because there is formation of nitrates and nitrite with soil mineral, which are good fertilizers.
Explanation of Solution
Given information: The reaction is as follows:
Temperature
a)The standard free energy of formation of NO
The equation for the reaction of
The standard free energy change for the formation of
Here,
The Gibbs energy for the reaction is as follows:
The standard free energy of formation of any element in its stable allotropic form at
From appendix 2, the values of the standard free energy of formation of the compounds are as follows:
Substitute the values of the standard free energy of formation of the compoundsand
Therefore, thestandard free energy change for the formation of
b)
The equation for the reaction of
The equilibrium pressure constant is calculated by using the expression as follows:
Here,
Substitute the values of
Therefore, the equilibrium pressure constant is
Given information: The reaction is as follows:
Temperature
c)The equilibrium pressure for the given reaction
The equation for the reaction of
The standard enthalpy change of the reaction (
Here,
The enthalpy for the reaction is as follows:
From appendix 2, the values of the standard enthalpy change for the formation of the substances are as follows:
Substitute the values of the standard enthalpy change for the formation of the substances in the above expression as follows:
The temperatures are converted from degree Celsius to Kelvin as follows:
The equilibrium pressure for this reaction at a temperature of
Here,
Substitute the values of
The value of
Hence, the equilibrium pressure at a temperature of
d)Lightning helps to produce better crops
In the atmosphere, nitrogen molecules are present. Two nitrogen atoms are tightly boundedto each other. In lightening, electrical energy is generated, which has enough energy to break the bonds of the nitrogen atoms in the air. It combines with oxygen to form
The equation for the reaction of
Hence, lightening helps in the production of better crops because there is formation of nitrates and nitrite with soil mineral, which are fertilizers.
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Chapter 18 Solutions
CHEMISTRY(HARDCOVER W/CODE) CUSTOM
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