Enthalpy Change Calculator - Calculator Suite

Formation Enthalpy Calculator

Reactants (comma-separated ΔH°f values):

Products (comma-separated ΔH°f values):

Chemical Equation (optional):

Bond Energy Calculator

Bonds Broken (energy required):

Bonds Formed (energy released):

Calorimetry Calculator

Mass of substance (g):

Specific heat capacity (J/g°C):

Temperature change (°C):

Phase Change Calculator

Substance:

Mass (g):

Enthalpy of fusion/vaporization (kJ/mol):

Molar mass (g/mol):

Enthalpy Theory & Reference

Key Concepts:

Enthalpy (H):

The total heat content of a system at constant pressure. ΔH = H(products) - H(reactants)

Exothermic:

ΔH < 0. Heat is released to surroundings. Products have lower energy than reactants.

Endothermic:

ΔH > 0. Heat is absorbed from surroundings. Products have higher energy than reactants.

Important Formulas:

ΔH°reaction = Σ ΔH°f(products) - Σ ΔH°f(reactants)

ΔH = Energy to break bonds - Energy to form bonds

q = mcΔT (calorimetry)

q = nΔH (phase changes)

Standard Enthalpies of Formation (kJ/mol):

H₂O(l)
-285.8

CO₂(g)
-393.5

CH₄(g)
-74.8

NH₃(g)
-46.1

Common Bond Energies (kJ/mol):

H-H
436

O=O
498

C-H
414

O-H
463

🔥 Enthalpy Change Calculator