Yes, photosynthesis is a chemical change. It involves a complex series of chemical reactions in which carbon dioxide and water are converted into glucose and oxygen, using sunlight as an energy source. 1
Well, this was just a simple answer. But there are few more things to know about this topic which will make your concept super clear.
So let’s dive right into it.
Key Takeaways: Is Photosynthesis a Physical or Chemical Change?
- Photosynthesis is a chemical change because it involves a series of chemical reactions that convert reactants (CO2 and H2O) into products (glucose and O2).
- Photosynthesis requires the absorption of light energy to drive the chemical reactions, which is characteristic of chemical changes.
- Unlike physical changes, photosynthesis does not involve a change in the physical properties or state of the substances involved.
Why is photosynthesis a chemical change?
Photosynthesis is considered a chemical change because it involves a series of chemical reactions that transform one set of substances (reactants) into another set of substances (products). These reactions occur within the chloroplasts of plant cells and some bacteria, primarily in the presence of sunlight. 2
During photosynthesis, plants use the energy from sunlight to convert carbon dioxide (CO2) and water (H2O) into glucose (C6H12O6) and oxygen (O2). 3 This process can be summarized by the following chemical equation: 4 5
6CO2 + 6H2O + sunlight → C6H12O6 + 6O2
This equation represents the overall reaction of photosynthesis, but the process actually involves multiple intermediate steps and complex biochemical pathways.
The chemical change occurs because the arrangement of atoms and the bonding patterns of the reactants (CO2 and H2O) are rearranged to form entirely new compounds (C6H12O6 and O2). The energy from sunlight is absorbed by chlorophyll and other pigments within the chloroplasts, which facilitates the necessary chemical reactions.
In summary, photosynthesis is considered a chemical change because it involves the conversion of reactants into products through a series of chemical reactions driven by energy input.
Why is photosynthesis not a physical change?
Photosynthesis is not considered a physical change because it does not involve a change in the physical properties or state of the substances involved. In a physical change, the substance undergoes a transformation that does not alter its chemical composition.
In photosynthesis, the reactants (carbon dioxide and water) are chemically converted into products (glucose and oxygen) through a series of complex biochemical reactions. The atoms in the reactants are rearranged to form entirely new compounds with different chemical properties.
Additionally, photosynthesis requires the absorption of light energy by pigments, such as chlorophyll, to drive the chemical reactions. 6 This energy absorption facilitates the breaking and formation of chemical bonds, which is a characteristic of chemical changes.
Furthermore, the rate of photosynthesis can be affected by factors such as temperature, CO2 concentration, and the presence of specific enzymes. 7 These factors influence the speed and efficiency of the biochemical reactions occurring during photosynthesis, further indicating its chemical nature.
In summary, photosynthesis involves chemical reactions that result in the formation of new compounds with distinct properties. It is not merely a rearrangement of molecules or a change in physical state, making it a chemical change rather than a physical one.
Further reading
Is Sublimation a Physical or Chemical Change?
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?
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References
- Intro to photosynthesis (article) | Khan Academy. (n.d.). Khan Academy. https://www.khanacademy.org/science/ap-biology/cellular-energetics/photosynthesis/a/intro-to-photosynthesis
- Alberts, B., Johnson, A., Lewis, J., Raff, M., Roberts, K., & Walter, P. (2002, January 1). Chloroplasts and Photosynthesis – Molecular Biology of the Cell – NCBI Bookshelf. Chloroplasts and Photosynthesis – Molecular Biology of the Cell – NCBI Bookshelf. https://www.ncbi.nlm.nih.gov/books/NBK26819/
- Photosynthesis. (n.d.). Photosynthesis. https://education.nationalgeographic.org/resource/photosynthesis
- Study.com https://study.com/learn/lesson/photosynthesis-concept-equation-steps.html
- Nace, T. (2019, August 26). The Photosynthesis Equation Made Easy. Forbes. https://www.forbes.com/sites/trevornace/2019/08/26/the-photosynthesis-equation-made-easy/
- Molnar, C., & Gair, J. (n.d.). 5.1: Overview of Photosynthesis – Concepts of Biology – 1st Canadian Edition. 5.1: Overview of Photosynthesis – Concepts of Biology – 1st Canadian Edition. https://opentextbc.ca/biology/chapter/5-1-overview-of-photosynthesis/
- Rsc.org https://edu.rsc.org/download?ac=12620
