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changes Around us, Exercise (Answer key), CH- 6, Q NO 1] ch0ose the correctoption-, a)→ BUYning, a new substance is formed., ) physical and reversible, d)→ ITrevessible and desixable change-, e Desixable change, Lusd, Q.NO.2, fill in the blanks cwith the coord's given, in the brackets, ., a) → reversiblechanges, b) Fast a, c) desirable, d) natual, e) Physical, O NO.3 state whether he following statements ore True ox fause, a)→ False, b) True, c) False, d) True, e) False, (page no.1)

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Q NO.4 Classify the following into physical ond chemicalchanges, Physical changes:- i)melting of an ice.creom., melting of wax, 1) righting of bulb, IN) Formation of fog, ) Formation of clouds, har, chemical chonges., :-) Baking of cake, )BUrning of paper, m)Boiling of egg, W) ighting of a matchstick, ) FOrmation of coal, vI) curdling of milk, Q.NO.5 Answer the following questions in short., a) List three main causes of change., Pressure, Heat and mixing of substances., b Give two examples for each of the fallowing, s/manmade changes) constu chion of building, D) paper cutting, ") Reversible changes:- a) melting of ice, ) Dissolving sait in water

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in) Undesixoble changes - a) Rotting of foad, 6) Orastic changes, in wealher, No C state ane difference between desirable changes, and undesirable changes., Desirable changes- changes that are use ful, gre called desinable changes, Undesivable changes - changes that are not useful, and may, even be harmful, mow, ore called undesixable changes., Q. NO. 6, Define the fallocuwing, a) Irreversible changes - changes which connot be, reversed, the conditions are called nreversible changes., simply by chonging, b Fast changes- The changes that occuves in a, shoxt time ore called fast changes -, c) chemical changes: A chemical change is a change, in which, formed which have properties that are, different faom the original substonces, new substances are

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Q. NO 7 Gve reason6., Digestion isa chemical change as well as e, physical change, ->, Because food is physically booken down by, chewing and chemically bxoken down bf digestive, enzimes in the saliva and the acid in the stamach, metals are Used for making tools, Metal's are used for making tools; because they, Are ased con strong and ens to shape-, Q NO 8 Answer the fallowing questions in dejai, O How is the melting of wax diffexent fom the, burning of wox ?, The mel ting of wax is n physical.chonge,because, Lonly ont state of matter is changing., In burning of candle the produchon of corsbon, dioxide dnd wates vapoux during the burping, ot wax is a chemical change, How does mixing bTing about achange ? EXploin, with the help of an exemple, → when twoor more substances are mixed, may form a mixture or react with each other to, form o new substan ce., exomple-when salt is mixed wfth waterit, forms a salt soluhion., they