Enthalpies of formation of CO(g), CO2(g) | Class 11 Chemistry Chapter Thermodynamics, Thermodynamics NCERT Solutions

Question:

Enthalpies of formation of CO(g), CO2(g), N2O(g) and N2O4(g) are –110, – 393, 81 and 9.7 kJ mol–1 respectively. Find the value of ΔrH for the reaction:

N2O4(g) + 3CO(g) → N2O(g) + 3CO2(g)

Answer:

ΔrH for a reaction is defined as the difference between ΔfH value of products and ΔfH value of reactants.

ΔrH = \sum  ΔfH (products) - \sum  ΔfH (reactants)

For the given reaction,

N2O4(g)+ 3CO(g)  →  N2O(g) + 3CO2(g)

ΔrH = [{ΔfH (N2O) + 3ΔfH(CO2)}  -  {ΔfH(N2O4) + 3ΔfH(CO)}]

Substituting the values of ΔfH for N2O, CO2, N2O4,and CO from the question, we get:

ΔrH = [{81 KJ mol-1 + 3(-393) KJ mol-1} - {9.7KJ mol-1 + 3(-110)KJ mol-1}]

ΔrH = -777.7 KJ mol-1

Hence, the value of ΔrH for the reaction is -777.7 KJ mol-1.


Study Tips for Answering NCERT Questions:

NCERT questions are designed to test your understanding of the concepts and theories discussed in the chapter. Here are some tips to help you answer NCERT questions effectively:

  • Read the question carefully and focus on the core concept being asked.
  • Reference examples and data from the chapter when answering questions about Thermodynamics.
  • Review previous year question papers to get an idea of how such questions may be framed in exams.
  • Practice answering questions within the time limit to improve your speed and accuracy.
  • Discuss your answers with your teachers or peers to get feedback and improve your understanding.

Comments

Comment(s) on this Question

Welcome to the NCERT Solutions for Class 11 Chemistry - Chapter . This page offers a step-by-step solution to the specific question from Excercise 1 , Question 12: Enthalpies of formation of CO(g), CO2(g), N2O(g) and N2O4(g) are –110, – 393, 81 and 9.7....