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प्रश्न
Define exothermic reactions. Give two examples of each.
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उत्तर
Exothermic reactions: The chemical reaction in which heat is given out is called exothermic reactions. It causes rise in temperature. .
e.g. (i) When carbon bums in oxygen to form carbon dioxide, a lot of heat is produced.
C + O2 → CO2 + heat.
When water is added to quicklime a lot of heat is produced which boils the water.
CaO + H2O → Ca (OH)2 + Heat.
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संबंधित प्रश्न
State the effect of an endothermic reaction.
Give scientific reason.
While preparing dilute sulphuric acid from concentrated sulphuric acid in the laboratory, the concentrated sulphuric acid is added slowly to water with constant stirring.
Give an example of the following chemical changes.
A reaction involving blue solution.
State the following reaction whether heat is evolved or absorbed –
water is added to quicklime
Give a balanced equation for the following type of reaction:
A catalytic, reversible, exothermic reaction.
Give an example with a balanced equation, of the following reaction:
photochemical reaction
Select the correct answer from the options given below:
State the gaseous product formed, when
Two gases one of them neutral combines by absorption of light energy.
Classify the following reaction into Exothermic and Endothermic reactions.
Magnesium ribbon when burned in air, it forms magnesium oxide.
Match the following:
| Colum I | Column II | ||
| 1. | Alloying | a. | Exothermic change |
| 2. | Crystallization | b. | Periodic change |
| 3. | Soap powder + water | c. | Mixing of molten solids |
| 4. | Seasonal changes | d. | Pure solid |
Give scientific reason.
While preparing dilute sulphuric acid from concentrated sulphuric acid in the laboratory, the concentrated sulphuric acid is added slowly to water with constant stirring.
