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प्रश्न
Define exothermic reactions. Give two examples of each.
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 exothermic reaction on the surroundings.
Identify the endothermic and exothermic reaction.
\[\ce{2KClO_{3(s)}->[\Delta] 2KCl_{(s)} + 3O2}\]
Why energy is involved in a chemical change?
State the effects of endothermic and exothermic reactions on the surroundings.
Explain the term energy changes in a chemical change or reaction.
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 examples of the endothermic process.
Complete the following table:
| Chemical Reactions | Name reaction type |
| \[\ce{C(s) + O2(g) -> CO2(g)}\] | (a) ________ |
| \[\ce{Zn(s) + CuSO4(aq) ->}\] (b) _________ | Displacement reaction |
| \[\ce{2Cu(s) + O2(g) ->[heat] 2CuO(s)}\] | (c) _________ |
| \[\ce{C(s) + 2H2(g) -> CH4(g)}\] | (d) _________ |
| \[\ce{CaO(s) + H2O(l) -> Ca(OH)2(aq) + heat}\] | (e) _________ |
| \[\ce{CaCO3(s) + Heat ->}\] (f) _________ | Endothermic Reaction |
Give a 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 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.
