# Calculating delta H of reaction using bond energies?

• Chemistry
• needhelpwithchem
In summary, the formula for calculating delta H of a reaction using bond energies is: ∆H = Σ (bond energy of bonds broken) – Σ (bond energy of bonds formed). Bond energies can be found in reference tables or databases and are typically listed in units of kilojoules per mole (kJ/mol). They can be negative, indicating an exothermic reaction. Calculating delta H allows us to determine the energy released or absorbed in a reaction and provides insight into its stability and spontaneity. However, there are limitations to using bond energies, as they are average values and may not accurately reflect the specific conditions of a reaction.
needhelpwithchem
Homework Statement
Relevant Equations
delta H = q
Hi, I have been stuck for hours, i do not understand how i am supposed to use bond energy values for this question like it asks when bond energy values are for molecules in the gas state. The first molecule reactant is a liquid and the second reactant has resonance. I have 0 idea how to approach this. Please help

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PF is like the Peanuts strip where Snoopy is waiting to cross the street and the signal turns green, "You have to move your feet." Make some sort of attempt.

## 1. What is delta H of reaction?

Delta H of reaction (ΔHr) is the change in enthalpy of a chemical reaction, which is a measure of the energy released or absorbed during the reaction. It is also known as the heat of reaction.

## 2. What are bond energies?

Bond energies are the amount of energy required to break a particular type of bond between two atoms in a molecule. They are measured in units of kilojoules per mole (kJ/mol).

## 3. How do you calculate delta H of reaction using bond energies?

The formula for calculating delta H of reaction using bond energies is: ΔHr = ∑(bond energies of bonds broken) - ∑(bond energies of bonds formed). This means you add up the bond energies of all the bonds broken in the reactants and subtract the bond energies of all the bonds formed in the products.

## 4. Why is calculating delta H of reaction using bond energies useful?

Calculating delta H of reaction using bond energies is useful because it provides a way to estimate the energy released or absorbed during a chemical reaction. It can also help predict the stability of a molecule and its reactivity.

## 5. What are some limitations of using bond energies to calculate delta H of reaction?

There are a few limitations to using bond energies to calculate delta H of reaction. One limitation is that it assumes all bonds in the reactants and products are broken or formed simultaneously, which is not always the case. It also does not account for any changes in bond lengths or bond angles during the reaction. Additionally, bond energies are average values and may not accurately represent the specific bonds in a particular molecule.

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