LO3 - Chemical Energetics - Questions

Carboxyl・2 minutes read

The text discusses the formation of nitrogen monoxide as an atmospheric pollutant, enthalpy changes in reactions, the process of photosynthesis, bond energy calculations, and energy profile diagrams for reactions, emphasizing the importance of energy in bond breaking and formation. It explains how positive enthalpy changes indicate endothermic reactions and provides detailed calculations on bond energies and enthalpy changes for different reactions.

Insights

  • Nitrogen monoxide is highlighted as an atmospheric pollutant causing eye and skin irritation, formed in car engines through the reaction of nitrogen and oxygen, showcasing the environmental impact of human activities on air quality.
  • The text emphasizes the importance of understanding enthalpy changes in reactions, with positive values indicating endothermy and the necessity to calculate the energy involved in bond breaking and formation accurately to determine the overall energy changes in chemical processes.

Get key ideas from YouTube videos. It’s free

Recent questions

  • What is the role of nitrogen monoxide in the atmosphere?

    Nitrogen monoxide causes eye and skin irritation.

  • How is endothermy indicated in reactions?

    Positive enthalpy change signifies endothermy.

  • What is the process of photosynthesis?

    Photosynthesis involves carbon dioxide, water, glucose, and oxygen.

  • How are endo and exo reactions differentiated?

    Endo and exo reactions are based on bond breaking and formation.

  • How is activation energy calculated in reactions?

    Activation energy is determined by energy profile diagrams.

Related videos

Summary

00:00

Enthalpy Changes in Chemical Reactions

  • Starting the recording with MCQs and the third question
  • Nitrogen monoxide as an atmospheric pollutant causing eye and skin irritation
  • Formed in car engines by the reaction of nitrogen and oxygen
  • Positive enthalpy change indicates endothermy
  • Analyzing energy taken in and given out for endo and exo reactions
  • Understanding enthalpy changes from reactants to products
  • Photosynthesis process involving carbon dioxide, water, glucose, and oxygen
  • Clarifying misconceptions about glucose as a source of energy and oxygen production
  • Differentiating between endo and exo reactions based on bond breaking and formation
  • Activation energy, enthalpy change, and energy profile diagrams for catalyzed reactions and reverse reactions

16:07

Understanding Enthalpy Change and Activation Energy

  • The activation energy of the reverse reaction is +447 for the forward reaction and will become the reactant for the reverse reaction.
  • Activation energy is never negative, and in enthalpy change, negative values are adjusted.
  • Positive enthalpy change indicates that the energy needed to break bonds is greater than the energy released during bond formation.
  • The products in an endothermic reaction are at a higher energy level than the reactants.
  • The energy profile diagram for a reaction should include reactants, products, enthalpy change, and activation energy.
  • The amount of energy given out during a reaction is measured at 80 joules, indicating a negative enthalpy change.
  • To determine the bond energy of one SF bond, calculate the energy for breaking and forming bonds.
  • The enthalpy change is calculated by subtracting the energy of bonds formed from the energy of bonds broken.
  • In a reaction between chlorine and carbon monoxide, 230 kilojoules of energy is released, indicating a negative enthalpy change.
  • To calculate the energy of the bond between carbon and oxygen in carbon monoxide, use the information provided to determine the bond energy.

32:12

Bond Energy Shifts and Calculations Explained

  • X-band energy is discussed, with a focus on the shift from plus to minus.
  • The concept of bond energy is explored, emphasizing the positivity of energy required for bond breaking.
  • A practical example is given regarding the energy released when sulfur burns, with calculations based on moles and molar mass.
  • The distinction between bond breaking and bond formation in terms of energy is explained.
  • A detailed calculation is provided for the energy needed to break specific bonds, with a focus on different types of bonds.
  • The energy taken in during bond breaking is calculated, with specific values for different types of bonds.
  • The energy release during bond formation is discussed, with calculations based on the number of bonds formed.
  • The enthalpy change for the complete combustion of one mole of a compound is calculated, emphasizing the importance of numerical accuracy.
  • The total energy required to break a mole of iodine and chlorine bonds is calculated, with a focus on the energy given out during bond formation.
Channel avatarChannel avatarChannel avatarChannel avatarChannel avatar

Try it yourself — It’s free.