AP Chemistry Flashcards: Enthalpy of Formation
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.
What is the formula for calculating the standard enthalpy of a reaction using standard enthalpies of formation?
The formula is ΔH°reaction = ΣΔHf°products − ΣΔHf°reactants.
Card 1 of 10
All Flashcards (10)
What is the formula for calculating the standard enthalpy of a reaction using standard enthalpies of formation?
The formula is ΔH°reaction = ΣΔHf°products − ΣΔHf°reactants.
What is the relationship between the standard enthalpies of formation (ΔHf°) and the standard enthalpy of a reaction (ΔH°reaction)?
The standard enthalpy of a reaction is calculated by finding the difference between the sum of the ΔHf° of the products and the sum of the ΔHf° of the reactants.
In the formula for ΔH°reaction, what does the term ΣΔHf°reactants represent?
It represents the sum of the standard enthalpies of formation for all the reactants in the reaction.
To calculate the enthalpy change for a reaction, what specific thermodynamic values must you look up in a table?
You must look up the standard enthalpies of formation (ΔHf°) for each of the products and reactants.
What can be calculated using tables of standard enthalpies of formation?
The standard enthalpy change for a chemical or physical process (ΔH°reaction) can be calculated.
What is the general process for calculating the enthalpy change of a reaction using standard enthalpies of formation?
First, sum the standard enthalpies of formation for all products. Then, subtract the sum of the standard enthalpies of formation for all reactants.
In the formula for ΔH°reaction, what does the term ΣΔHf°products represent?
It represents the sum of the standard enthalpies of formation for all the products in the reaction.
Which side of the reaction equation is subtracted in the standard enthalpy of reaction calculation?
The sum of the standard enthalpies of formation for the reactants (ΣΔHf°reactants) is the term that is subtracted.
If you are given a chemical equation and a table of standard enthalpies of formation, what calculation can you perform?
You can calculate the standard enthalpy change for that specific chemical reaction (ΔH°reaction).
What does the symbol ΔH°reaction represent?
It represents the standard enthalpy of a reaction, which is the overall enthalpy change for a given chemical or physical process.