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प्रश्न
Define exothermic and endothermic changes. Give two example in each case.
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उत्तर
Exothermic Reaction
The chemical reactions which proceed with the evolution of heat energy are called exothermic reactions.
Examples:
Carbon burns in oxygen to form carbon dioxide and heat energy is produced.
C + O2 → CO2 + Heat
Water added to quick lime (calcium oxide), slaked lime (calcium hydroxide) is produced with a lot of heat energy.
CaO + H2O → Ca(OH)2 + Heat
Endothermic Reaction
The chemical reactions which proceed with the absorption of heat energy are called as endothermic reactions.
Examples:
When nitrogen and oxygen are heated together to a particular temperature of about 3000oC, nitric oxide gas is formed.
N2 + O2 + Heat → 2NO
Calcium carbonate decomposes into carbon dioxide and calcium oxide when heated to a temperature of about 1000oC.
CaCO3 + Heat → CaO + CO2
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संबंधित प्रश्न
FILL IN THE BLANK
In a................ reaction heat energy is absorbed.
Give an example of the following chemical changes.
An exothermic and an endothermic reaction involving carbon as one of the reactants.
State which type of chemical reaction proceeds with the absorption of heat energy.
State the following reaction whether heat is evolved or absorbed –
water is added to quicklime
Supply of energy may be required to initiate a reaction. State the different forms with a suitable example of reactions initiated by the supply of energy.
Complete the statement by filling in the blank with the correct word:
The reaction of hydrogen burning in oxygen to give a neutral liquid is an example of ________ reaction.
Give examples of the endothermic process.
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 reasons.
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.
