Yash V.
asked • 04/15/17If we mix water and flour to make dough then the formation of dough is a physical change or chemical change?
There is no heat or anything is applied. Just water and flour and beating it to make dough. So is it a physical or chemical change?
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2 Answers By Expert Tutors
J.R. S. answered • 04/15/17
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Mixing flour and water would be a physical change, since neither the water nor the flour are changing their chemical makeup. The water is still water, and the flour is still flour, and if you were to evaporate or remove the water after mixing, you would still have the original flour.
Katie B.
While the mere addition of flour to water is a mixture, the process of kneading to form dough activates yeast, which changes its configuration irreversibly. You're incorrect.
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04/15/17
J.R. S.
tutor
The question didn't really say anything about yeast or kneading, so I respectfully disagree that adding water to flour would be a chemical change. And while I do agree with you that I wouldn't want to use the flour again after removal of the water, it is, nonetheless, still flour in an unchanged chemical state.
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04/15/17
Yash V.
I have stated that water and flour are beated to make dough. Kneading also come in that. So now does your answer change or not?
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04/15/17
J.R. S.
tutor
Not sure what "belated" means, but yes, I would change my answer if you are actually making dough. When I initially read the question, I believed it to be a basic chemistry question, as might be asked in intro chem. Such as "is mixing sugar and water a chemical or physical change?" However, if you are asking as a matter of practice, then I would have to agree that adding water to flour, then mixing and kneading into dough, would be a chemical change.
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04/15/17
J.R. S.
tutor
Sorry about the "belated", when I see it says "beated", but that also isn't really a word with which I'm familiar.
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04/15/17
Katie B.
My answer was right.
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04/16/17
Sel H.
But what about if no yeast added? will you consider it reversible?
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01/24/19
Katie B. answered • 04/15/17
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This would be a chemical change, as those can't be undone whereas a physical change can revert to the original state. You can't easily remove the water from the dough to get flour again, and, if you do, I personally wouldn't want to reuse it!
Mark M.
"Reversibility" is not part of the definition of chemical change. In a chemical change atoms are rearranged to change properties or composition thus creating a new chemical substance. Rust is an example.
Since the properties (substance) of the water and flour are not changed, mixing them is not a chemical change.
As to the yeast, that is the process of ingestion, digestion, and excretion.
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04/15/17
Katie B.
Even Wikipedia states, "In general a physical change is reversible using physical means." Think again. I stand by my answer 100%.
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04/16/17
Sean L.
freezing water to make ice and melting it
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05/31/21
Priski N.
But, if you mix flour and water, the flour changes into gluten, doesn't it? So, isn't it a chemical change?
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08/23/21
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Michael F.
bake. I think a chemical change. "When flour and water are mixed together, water molecules hydrate the gluten-forming proteins gliadin and glutenin, as well as damaged starch and the other ingredients. The hydration process is achieved when protein and starch molecules create hydrogen bonds and hydrophilic interactions with the water molecules."05/03/22