Question

Making dough is a physical change while making a chapatti is a chemical change. Why? (Give three reasons)​

Answer 1

Explanation:

These two are physical changes as no new substance is formed. the only thing that happened during these two chemical changes were mixing with water and salt and change its form. Chemical changes were when you heat the chapatis and brown spots come on the chapatis. This reaction is called a Maillard reactions.

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Answer 2

Answer:

Once Curd formed from Milk it cannot revert back to milk, so it is an irreversible change. Due to the lactobacillus bacteria the curd formation takes place . Its formaion is irreversable & a chemical change because once the curd is formed , we cannot seperate the substances from it .