Q6 Give reasons : -
(i) All decomposition reactions are endothermic reactions.
(ii) Photosynthesis is considered as an endothermic reaction.
(iii) An iron knife kept dipped in a blue copper sulphate solution turns the blue solution light green.
(iv) When carbon dioxide is passed through lime water, it turns milky.
(v) Hydrogen being a highly inflammable gas and oxygen being a supporter of combustion, yet water which is a
compound made up of hydrogen and oxygen is used to extinguish fire.
Answers
1ST ANSWER:-
No, not all decomposition reactions are endothermic. A decomposition reaction can be both endothermic or exothermic. However, the latter is more common than the former. For example:-
- The decomposition of NO to N2 & O2 is exothermic.
- Decomposition of ozone (O3) to oxygen (O2) is exothermic.
2ND ANSWER:-
Photosynthesis is an endothermic reaction because sunlight energy is absorbed by green plants during this process.
3RD ANSWER:-
An iron knife kept dipped in blue copper sulphate solution changes to light green because iron being more reactive than copper displaces it from copper sulphate solution and forms iron sulphate.
4TH ANSWER:-
When carbon dioxide gas is passed through or over limewater, it turns milky due to the formation of calcium carbonate.
5TH ANSWER:-
Water is compound of hydrogen and oxygen. water basically cools the comustible material so that its temperatur omes down below its ignition temp. this prevents the fire from spreading.