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Some Examples of Chemical Changes- 2 Video Lecture | Science Class 7

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FAQs on Some Examples of Chemical Changes- 2 Video Lecture - Science Class 7

1. What are some examples of chemical changes in everyday life?
Ans. Some examples of chemical changes in everyday life include burning wood, rusting of iron, cooking food, digestion of food in our body, and the fermentation of grapes to make wine.
2. How can we identify a chemical change?
Ans. There are several signs that can help us identify a chemical change. These include the formation of a new substance with different properties, a change in color, the release of gas, production of heat or light, and the formation of a precipitate (a solid that forms from a liquid solution).
3. What is the difference between a physical change and a chemical change?
Ans. A physical change is a change in the appearance or state of matter without any change in its chemical composition. Examples of physical changes include melting ice, boiling water, and crushing a can. On the other hand, a chemical change involves the formation of new substances with different properties. Examples of chemical changes include burning paper, cooking food, and the digestion of food in our body.
4. Why is it important to understand chemical changes?
Ans. Understanding chemical changes is important because it helps us understand how substances react with each other and how new substances are formed. It is crucial in fields such as chemistry, biology, and medicine, where knowledge of chemical reactions is essential in developing new drugs, understanding metabolic processes, and designing experiments.
5. Can physical changes be reversed?
Ans. Yes, physical changes can often be reversed. For example, if we melt ice, we can freeze it back into solid form. However, in chemical changes, the new substances formed cannot be easily reversed back to their original form. Once a chemical change occurs, it is usually difficult or impossible to revert the substances back to their original state.
111 videos|246 docs|28 tests
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