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Some Examples of Chemical Changes- 1 Video Lecture | Science Class 7 (Old NCERT)

FAQs on Some Examples of Chemical Changes- 1 Video Lecture - Science Class 7 (Old NCERT)

1. What is a chemical change?
Ans. A chemical change refers to a process in which one or more substances are transformed into new substances with different chemical compositions. It involves the breaking and forming of chemical bonds, resulting in the creation of entirely different substances.
2. What are some examples of chemical changes?
Ans. Some examples of chemical changes include the burning of wood, rusting of iron, digestion of food, fermentation of grapes to produce wine, and the reaction between baking soda and vinegar to create carbon dioxide gas.
3. How can you differentiate between a chemical change and a physical change?
Ans. A chemical change involves the formation of new substances with different chemical properties, while a physical change does not result in the formation of new substances. Physical changes only alter the physical appearance or state of a substance, such as melting ice into water or tearing a piece of paper.
4. Why is it important to understand chemical changes?
Ans. Understanding chemical changes is crucial because they play a significant role in various aspects of our daily lives. It helps us comprehend the reactions occurring in the natural world, such as digestion, combustion, and decay. Moreover, knowledge of chemical changes is vital in fields like medicine, manufacturing, and environmental science.
5. Are chemical changes reversible?
Ans. While some chemical changes are reversible, others are irreversible. Reversible chemical changes can be undone by applying specific conditions or reversing the reaction. For example, the formation and dissociation of water through the process of electrolysis is a reversible chemical change. On the other hand, irreversible chemical changes cannot be easily reversed or undone, such as the burning of paper or the cooking of food.
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