Sublimation is a physical change. It is the process in which a substance transitions directly from the solid phase to the gaseous phase without passing through the liquid phase. 1 In sublimation, the chemical composition of the substance remains the same, and only its physical state changes.
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Key Takeaways: Is Sublimation a Physical or Chemical Change?
- Sublimation is a physical change because it involves a change in the physical state of a substance without altering its chemical composition.
- During sublimation, the substance absorbs heat energy, weakening the intermolecular forces and allowing the solid particles to transition directly into the gas phase.
- Sublimation is not a chemical change because it does not involve a rearrangement of atoms or a change in the chemical composition of the substance.
Why is sublimation a physical change?
Sublimation is considered a physical change because it involves a change in the physical state of a substance without altering its chemical composition. 2 In sublimation, a solid directly converts into a gas without passing through the liquid phase. 3
During sublimation, the substance absorbs heat energy, which increases the kinetic energy of its particles.
As a result, the intermolecular forces holding the particles together weaken, and the solid particles break free and transition into the gas phase. When the gas particles cool down, they may condense back into a solid without undergoing a liquid phase.
Since sublimation involves a phase transition from solid to gas (or gas to solid), with no alteration in the chemical structure or composition of the substance, it is classified as a physical change.
Other examples of physical changes include melting, freezing, boiling, and condensation.
Why is sublimation not a chemical change?
Sublimation is not a chemical change because it does not involve a rearrangement of atoms or a change in the chemical composition of the substance. In a chemical change, the bonds between atoms are broken and new bonds are formed, resulting in a different substance with distinct properties. 4
In the case of sublimation, the substance undergoes a phase transition from a solid directly to a gas, or from a gas directly to a solid, without any alteration in its chemical structure.
The particles within the substance retain their original identity and arrangement.
Chemical changes, on the other hand, involve chemical reactions where the atoms of the substances involved are rearranged, leading to the formation of new compounds or substances.
These changes often involve the breaking and formation of chemical bonds, resulting in different properties and compositions.
Since sublimation does not involve any chemical reactions or changes in the composition of the substance, it is classified as a physical change rather than a chemical change.
Further reading
Is Decomposition a Chemical Change?
Is Combustion a Physical or Chemical Change?
Is Condensation a Physical or Chemical Change?
Is Sugar Dissolving in Water a Physical or Chemical Change?
Is Salt Dissolving in Water a Physical or Chemical Change?
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References
- Mechanisms of Introduction Into the Environment. (2018, August 17). Mechanisms of Introduction Into the Environment – ScienceDirect. https://doi.org/10.1016/B978-0-12-804422-3.00004-3
- Study.com https://homework.study.com/explanation/is-sublimation-a-physical-or-chemical-change.html
- Sublimation and deposition – Energy Education. (n.d.). Sublimation and Deposition – Energy Education. https://energyeducation.ca/encyclopedia/Sublimation_and_deposition
- What happens to chemical bonds when a chemical reaction takes place? (n.d.). Encyclopedia Britannica. https://www.britannica.com/question/What-happens-to-chemical-bonds-when-a-chemical-reaction-takes-place
