looks mother forgot to keep the kneaded dough outside the fridge in the heat. on seeing the morning some changes were noticed in the flour. this change is physical or chemical ?
Answers
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looks mother forgot to keep the kneaded dough outside the fridge in the heat. on seeing the morning some changes were noticed in the flour. this change is Chemical change.
Reason:-
- It is because fermentation takes place which is an irreversible process.
- When the dough is kept in the open, it becomes a medium for the growth of microorganisms( especially yeast).
- The water activity becomes appropriate for the microorganisms to grow on it and bring about fermentation.
- The carbohydrates present in the dough help in the growth of saprophytic fungi, bacteria and yeast that break down carbohydrates into simple sugars, thereby emitting carbon dioxide and ethanol.
- This changes the appearance( rises up due to the gas produced) and smell of the dough( foul smell) and it becomes unfit to be used further.
Physical Change:-
1. A physical change is temporary .
2. A physical change is reversible .
3. No new substances are formed after a physical change .
4. After a physical change, the mass of the substances remains unaltered .
5. Example : Melting of ice , evaporation of liquid , freezing of water etc
Chemical change:-
1. A chemical change is permanent .
2. A chemical change is Irreversible .
3. New substances are formed after a chemical change .
4. The mass of the individual substance undergoing a chemical change is altered .
5. Example : Photosynthesis , fermentation , respiration etc .
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