
Calculate the enthalpy of combustion of methane, if the standard enthalpies of formation of methane, carbon dioxide, water are , and ?
Answer
412.2k+ views
1 likes
Hint: Enthalpy of combustion is the change in enthalpy when one mole of the compound is completely burn in the presence of excess of oxygen with all the reactants and products in their normal states under normal conditions, i.e. and .
Where, is the rate of change of enthalpy of reaction
is the rate of change enthalpy of the product
is the rate of change enthalpy of the reactants.
Complete Step By Step Answer:
As we know the enthalpy of combustion is
We also know that the enthalpy is associated with the combustion reaction, i.e.
We have to balance the given chemical reaction:
With heat of formation values given by the following table:
Hence according to the fact, the rate of change of enthalpy of the reaction is equal to the difference of the summation of rate of change of enthalpy of the product and the summation of rate of change of enthalpy of the reactants. This mathematically can be representing as:
By keeping the given values we will get:
Hence, the enthalpy of combustion is .
Note:
Always remember, since enthalpy is a state function, the sign of the enthalpy of a reaction changes when the process is reversed, which means it does not depend upon the path. Hence, whatever reaction is used , the enthalpy of the final reaction is not affected.
Where,
Complete Step By Step Answer:
As we know the enthalpy of combustion is
We also know that the enthalpy is associated with the combustion reaction, i.e.
We have to balance the given chemical reaction:
With heat of formation values given by the following table:
Substance | |
| |
| |
| |
Hence according to the fact, the rate of change of enthalpy of the reaction is equal to the difference of the summation of rate of change of enthalpy of the product and the summation of rate of change of enthalpy of the reactants. This mathematically can be representing as:
By keeping the given values we will get:
Hence, the enthalpy of combustion
Note:
Always remember, since enthalpy is a state function, the sign of the enthalpy of a reaction changes when the process is reversed, which means it does not depend upon the path. Hence, whatever reaction is used , the enthalpy of the final reaction is not affected.
Recently Updated Pages
Master Class 11 Accountancy: Engaging Questions & Answers for Success

Master Class 11 Social Science: Engaging Questions & Answers for Success

Master Class 11 Economics: Engaging Questions & Answers for Success

Master Class 11 Physics: Engaging Questions & Answers for Success

Master Class 11 Biology: Engaging Questions & Answers for Success

Class 11 Question and Answer - Your Ultimate Solutions Guide

Trending doubts
The non protein part of an enzyme is a A Prosthetic class 11 biology CBSE

What is a zygomorphic flower Give example class 11 biology CBSE

The deoxygenated blood from the hind limbs of the frog class 11 biology CBSE

What is the function of copulatory pads in the forelimbs class 11 biology CBSE

Which of the following is nitrogenfixing algae a Nostoc class 11 biology CBSE

Renal portal system of frog is significant in A Quick class 11 biology CBSE
