AP Chemistry Flashcards: Bond Enthalpies
Written by AP Content Team, Verified for 2026 AP Exams, Last updated: May 2026
Review key ideas with interactive flashcards. This set includes 10 cards to help you master important concepts.
How is the total energy released when product bonds are formed estimated?
The energy released when forming product bonds is estimated by summing the average bond energies of all the new bonds that are formed.
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How is the total energy released when product bonds are formed estimated?
The energy released when forming product bonds is estimated by summing the average bond energies of all the new bonds that are formed.
Bond Enthalpy Calculation
A method to calculate the enthalpy change of a reaction by summing the average energies of bonds broken and subtracting the sum of the average energies of bonds formed.
What defines an endothermic reaction in terms of bond energies?
An endothermic reaction occurs when the energy required to break reactant bonds is greater than the energy released when forming product bonds.
If the energy released upon bond formation is greater than the energy required for bond breaking, what type of reaction is it?
The reaction is exothermic because more energy is released by forming bonds than is required to break them.
How is the total energy required to break reactant bonds estimated?
The energy required to break reactant bonds is estimated by summing the average bond energies of all the bonds that are broken.
What two opposing energy events occur during a chemical reaction involving bonds?
During a reaction, energy is required to break the bonds in reactants, and energy is released when new bonds are formed in the products.
Exothermic Reaction (Bond Energy Perspective)
A reaction where the energy released from forming product bonds is greater than the energy required to break reactant bonds.
How is the enthalpy change of a reaction calculated using bond energies?
The enthalpy change is calculated based on the average bond energies of bonds broken in the reactants and bonds formed in the products.
What happens to a system's potential energy during a chemical reaction?
During a chemical reaction, the breaking and/or forming of bonds changes the potential energy of the system.
A reaction has a positive enthalpy change calculated from bond energies. What does this indicate about the bonds involved?
This indicates the reaction is endothermic, meaning more energy was required to break the reactant bonds than was released by forming the product bonds.