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प्रश्न
What is the difference between dissolution of sugar and burning of sugar ?
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उत्तर
1. Dissolution of sugar:
- When sugar is dissolved in water it disappears. It we taste the solution, the sugar is still present in dissolved form.
- If water is evaporated we get back the sugar.
- So it is a physical and reversible change.
2. Burning of sugar:
- Fire activates a chemical reaction between sugar and oxygen. The oxygen in the air reacts with the sugar as the chemical bonds broke.
- Energy is released in the form of smoke.
- So, burning a sugar is a chemical change.
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संबंधित प्रश्न
Classify the following as chemical or physical change:
Rusting of almirah
Tick the most appropriate answer.
5. Photosynthesis requires
- heat energy.
- wind energy
- sunlight.
- sound energy
Fill in the blank
Changes that occur in nature are called ______
Classify the following as a physical or a chemical change.
Boiling of water
State which of the following terms connected with change of state of matter i.e.
(a) Melting
(b) Vaporisation
(c) Condensation
(d) Freezing
pertain to –
- Conversion of a liquid into a vapour or gas.
- Conversion of a liquid into a solid.
- Conversion of a solid into a liquid on heating.
Select the chemical changes from the following list of changes
Breaking of glass
Select the correct answer from the choice given below to complete the sentence
A change in which a substance retains its identity is a
______ change.
State which of the following 1 to 5 pertain to – A: Physical Change B: Chemical change :
- Sublimation.
- Fermentation.
- Liquefaction or condensation.
- Magnetization.
- Respiration.
Distinguish physical and chemical changes.
Tearing of sheet of paper into pieces is ______ By the process of Heating of water, change.
