Yes, decomposition is a chemical change. It involves the breakdown of a compound into simpler substances through a chemical reaction. 1 During decomposition, chemical bonds are broken, and new compounds or elements are formed, resulting in a change in the chemical composition and properties of the original substance.
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Key Takeaways: Is Decomposition a Chemical Change?
- Decomposition is a chemical change because it involves the breaking down of a substance into simpler components, resulting in the formation of new substances with different properties.
- Decomposition is not a physical change because it involves a fundamental alteration in the chemical composition of a substance, resulting in the formation of new chemical species.
- Physical changes refer to transformations that affect the physical properties of a substance, such as its shape, size, or state of matter, without changing its chemical identity.
Why is decomposition a chemical change?
Decomposition is considered a chemical change because it involves the breaking down of a substance into simpler components, resulting in the formation of new substances with different properties. 2 This process typically requires the input of energy and often involves the breaking of chemical bonds.
In a chemical reaction, decomposition occurs when a compound is broken down into two or more simpler substances. This can happen through various mechanisms such as heat, light, or the addition of a catalyst.
The bonds holding the atoms together within the compound are disrupted, leading to the formation of new bonds and the release of energy. This transformation is irreversible, as the original compound cannot be reconstituted from its decomposed components.
For example, the decomposition of hydrogen peroxide (H2O2) produces water (H2O) and oxygen (O2) gas. 3 When hydrogen peroxide is heated or exposed to a catalyst, it breaks down into its constituent elements through a chemical reaction.
The resulting water and oxygen have different properties from the original hydrogen peroxide, indicating a chemical change.
In summary, decomposition is a chemical change because it involves the breaking of chemical bonds within a compound, resulting in the formation of new substances with distinct properties.
Why is decomposition not a physical change?
Decomposition is not considered a physical change because it involves a fundamental alteration in the chemical composition of a substance, resulting in the formation of new chemical species. Physical changes, on the other hand, do not involve any changes in the chemical composition or the formation of new substances. 4 5
Physical changes refer to transformations that affect the physical properties of a substance, such as its shape, size, or state of matter, without changing its chemical identity. 6
Examples of physical changes include melting, freezing, boiling, evaporation, condensation, and dissolving. These changes are reversible, meaning the substance can be returned to its original state without any alteration in its chemical properties.
In contrast, decomposition involves the breaking of chemical bonds and the rearrangement of atoms, leading to the formation of different compounds or elements.
This process cannot be easily reversed, and the resulting substances have distinct chemical properties compared to the original substance. Therefore, decomposition is classified as a chemical change rather than a physical change.
Further reading
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?
Is Burning of a Candle a Physical or Chemical Change?
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References
- 11.5: Decomposition Reactions. (2016, June 27). Chemistry LibreTexts. https://chem.libretexts.org/Bookshelves/Introductory_Chemistry/Introductory_Chemistry_(CK-12)/11%3A_Chemical_Reactions/11.05%3A_Decomposition_Reactions
- Chemical decomposition – Wikipedia. (2017, May 1). Chemical Decomposition – Wikipedia. https://en.wikipedia.org/wiki/Chemical_decomposition
- Hydrogen peroxide – Wikipedia. (2019, November 30). Hydrogen Peroxide – Wikipedia. https://en.wikipedia.org/wiki/Hydrogen_peroxide
- Tennessee.edu https://extension.tennessee.edu/publications/Documents/W401.pdf
- Changes in Matter: Physical vs. Chemical Changes. (n.d.). Changes in Matter: Physical Vs. Chemical Changes. https://education.nationalgeographic.org/resource/changes-matter-physical-vs-chemical-changes
- Physical & Chemical Changes in Matter – Teachers (U.S. National Park Service). (n.d.). Physical & Chemical Changes in Matter – Teachers (U.S. National Park Service). https://www.nps.gov/teachers/classrooms/physical-chemical-changes-in-matter.htm
