Question

all are 2 mark question.plzz answer this

Why is respiration considered to be an exothermic reaction?

Why are decomposition reactions called the opposite of Combination reactions? Write equations for decomposition reactions.

Oil and Fat containing food items are flushed with Nitrogen. Why?

Soln:

Answer 1

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Here is your answer

Q. WHY IS RESPIRATION CONSIDERED TO BE AN EXOTHERMIC REACTION?

ANS. Respiration is considered to be an exothermic reaction because energy is evolved during this reaction.

C6H12O6+6O2=>6CO2+6H2O+Energy

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Q. WHY DECOMPOSITION REACTIONS ARE CALLED THE OPPOSITE OF COMBINATION REACTIONS? WRITE EQUATIONS FOR DECOMPOSITION REACTIONS.

ANS. In combination reactions, two or more compounds combine to form a single compound whereas in decomposition reactions, one compound splits up to form two or more simpler compounds.

EXAMPLE:

COMBINATION REACTION :
2H2+O2=>2H2O

DECOMPOSITION REACTION:
2H2O=>2H2+O2

From the above example, it is clear that decomposition reactions are the opposite of combination reactions.

EQUATIONS FOR DECOMPOSITION REACTIONS:
• 2NaCl=>2Na+Cl2

• CaCO3=>CaO+CO2

• 2H2O=>2H2+O2

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OIL AND FAT CONTAINING FOOD ITEMS ARE FLUSHED WITH NITROGEN. WHY?

ANS. Oil and fat containing food items are flushed with nitrogen to prevent rancidity. When the packets are flushed with unreactive gases like nitrogen they don't react with oxygen and hence rancidity is prevented.

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