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Question
Name the following:
The final product of the physical change involved during the ‘melting of a piece of wax’.
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Solution
Wax [CxHy]
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RELATED QUESTIONS
Classify the following as chemical or physical change:
Burning of paper and wood
Classify the changes involved in the following process as physical or chemical changes:
Photosynthesis
When a candle burns, both physical and chemical changes take place. Identify these changes. Give another example of a familiar process in which both the chemical and physical changes take place.
Tick the most appropriate answer.
5. Photosynthesis requires
- heat energy.
- wind energy
- sunlight.
- sound energy
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 |
Classify the following changes as physical or chemical.
Change is the law of nature and occurs in our everyday life, at all times and in all places.
Differentiate between the following change with a suitable example.
Periodic and non-periodic change
State the observations seen, when milk in a dish is kept aside for a few hours or more. Is the change which occurs – a physical change or a chemical change. Give reasons.
Select the chemical changes from the following list of changes
Boiling of milk.
Match the following
| Sr. No. | A | B | C |
| 1. | Melting | Change of state from liquid to solid | Ticking of clock |
| 2. | Condensation | Change of state from liquid to gas | Formation of ice cube |
| 3. | Evaporation | Change of state from solid to liquid | Collecting flowers |
| 4. | Freezing | Change of state from gas to liquid | Ice cube to water |
| 5. | Periodic change | Occurs at irregular time intervals | Water to steam |
| 6. | Non-periodic change | Occurs at regular time intervals | Steam to water drops |
