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Question
Compare the energy changes involved during a physical and a chemical change.
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Solution
- Physical change: No gain or loss of energy during physical change.
The energy required for completion of a physical change is released when the change is reversed. - Chemical change: Energy is either absorbed or evolved during the chemical change.
The energy in the form of light, percussion (pressure), or generally heat energy is required for a chemical change.
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RELATED QUESTIONS
Try segregating the things around you as pure substances or mixtures.
Match the columns.
| Column A | Column B |
| 1. a change which cannot be easily reversed | a. man-made change |
| 2 a change that repeats itself at regular intervals | b. chemical chang |
| 3. a change that is made by humans | c. physical change |
| 4. a change in which the original substance cannot be obtained | d. periodic change |
| 5. a change where no new substance is formed | e. irreversible change |
| f . slow change |
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