Enthalpy Change from Bond Energies Calculator: Δ H = Σ Ebonds broken - Σ Ebonds made

Enthalpy Change from Bond Energies Calculator

🔥 Thermochemistry & Bonding. Use the Enthalpy change from bond energies formula to find δh, energy of bonds broken, energy of bonds made: pick the value you want, type the others, and the answer updates as you go.

\Delta H = \sum E_{bonds\ broken} - \sum E_{bonds\ made}

Negative ΔH = exothermic.

ΔH (kJ/mol)Energy of bonds broken (kJ)Energy of bonds made (kJ)

ΔH-184 kJ/mol

Pick the ○ next to the value you want to find, fill in the others, and it solves as you type.

What each letter means

Quantity	Unit
ΔH	kJ/mol
Energy of bonds broken	kJ
Energy of bonds made	kJ

Worked example

Find the δh when Energy of bonds broken = 679 kJ, Energy of bonds made = 863 kJ.

Using Δ H = Σ Ebonds broken - Σ Ebonds made: ΔH = -184 kJ/mol.

Frequently asked questions

What is the formula for Enthalpy change from bond energies?

Δ H = Σ Ebonds broken - Σ Ebonds made. Negative ΔH = exothermic.

What do the letters stand for, and what units are used?

ΔH in kJ/mol, Energy of bonds broken in kJ, Energy of bonds made in kJ.

How do you calculate δh?

Put the values into Δ H = Σ Ebonds broken - Σ Ebonds made. For example, with Energy of bonds broken = 679 kJ, Energy of bonds made = 863 kJ, δh = -184 kJ/mol.

Can I solve for a different value?

Yes. In the calculator above, pick the circle next to any value (δh, energy of bonds broken, energy of bonds made) and fill in the others: it rearranges the formula for you.