Sublimation Enthalpy Calculator – Quickly Find ΔHsub Values

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The sublimation enthalpy calculator helps you find the energy needed to convert a solid directly into a gas. It uses the simple formula ΔH_sub = ΔH_fus + ΔH_vap, where ΔH_fus is the enthalpy of fusion and ΔH_vap is the enthalpy of vaporization.

By entering these two values, the calculator instantly provides the enthalpy of sublimation in kJ/mol.

For example, if a substance has ΔH_fus = 5.0 kJ/mol and ΔH_vap = 40.0 kJ/mol, the sublimation enthalpy will be 45.0 kJ/mol. This tool is widely used in chemistry and thermodynamics to study phase changes such as dry ice turning into gas.

Sublimation Enthalpy Calculator

Formula Used in the Calculator

Formula:

ΔHsub = ΔHfus + ΔHvap

ΔHsub = Enthalpy of sublimation (in kJ/mol)

ΔHfus = Enthalpy of fusion (in kJ/mol)

ΔHvap = Enthalpy of vaporization (in kJ/mol)

This shows that the energy required for sublimation equals the energy needed to melt and vaporize the substance.
A formula for enthalpy in sublimation.

Where:

  • ΔH_sub = Enthalpy of sublimation (in kJ/mol)
  • ΔH_fus = Enthalpy of fusion (in kJ/mol) (energy required to melt a solid into a liquid)
  • ΔH_vap = Enthalpy of vaporization (in kJ/mol) (energy required to convert a liquid into a gas)

How to Use the Calculator

  1. Enter the Fusion Enthalpy (ΔH_fus) in the provided input box.
  2. Enter the Vaporization Enthalpy (ΔH_vap) in the second input box.
  3. Click the "Calculate Sublimation Enthalpy" button to compute the result.
  4. The calculator will display the sublimation enthalpy value in kJ/mol.

This tool is useful in thermodynamics and chemistry for understanding phase changes, particularly for sublimation processes like dry ice (solid CO₂) turning into gas directly.

Sublimation Calculation apps

Example Calculation for Sublimation Enthalpy

Let's assume we have a substance with the following enthalpies:

  • Temperature: 300 K (if required)
  • Fusion Enthalpy (ΔH_fus) = 5.0 kJ/mol
  • Vaporization Enthalpy (ΔH_vap) = 40.0 kJ/mol
Example of Sublimation Enthalpy Calculator.

Why is Sublimation Enthalpy Important?

  • Industrial Uses: Freeze-drying food/pharmaceuticals.
  • Planetary Science: Explains comet tails (sublimating ices).
  • Material Engineering: Critical for vapor deposition techniques.
Infographic showing sublimation enthalpy calculation with dry ice turning from solid to gas, arrows for ΔHfus and ΔHvap, and formula ΔHsub = ΔHfus + ΔHvap.

Final Answer:

The sublimation enthalpy for this substance is 45.0 kJ/mol.

This means that 45.0 kJ of energy is required per mole to convert the substance directly from a solid to a gas.

All About Sublimation Resources

References

  1. NIST Chemistry WebBook – Authoritative thermodynamic data.
  2. Atkins, P., & de Paula, J. (2018). Physical Chemistry (11th ed.). Oxford University Press. Theoretical foundation.

FAQs

The enthalpy of sublimation for potassium (K) is approximately 89.5 kJ/mol. This value represents the energy required to convert solid potassium directly into its gaseous form without passing through the liquid phase.

The sublimation enthalpy is the total energy required for a substance to transition from a solid to a gas. It is the sum of the fusion enthalpy (solid to liquid) and the vaporization enthalpy (liquid to gas). This makes it an essential thermodynamic property for substances like dry ice and other materials that undergo direct phase transitions.

Yes, the calculator can be used for any substance as long as you have the required values for the fusion enthalpy and vaporization enthalpy. Each substance may have its own unique values for these enthalpies, so make sure to input the correct data for accurate results.