Physical change kya hai? Udaaharan do.

Physical change vo badlaav hai jismein sirf aakaar, size ya avastha jaisi physical properties badalti hain aur koi naya padaarth nahi banta. Kaagaz ki naav banaana, gubbaare ki hawa nikaalna, chalk ko powder banaana aur baraf pighalna iske udaaharan hain: kaagaz, rubber, chalk aur paani wahi padaarth rehte hain.

Chemical change kya hai? Udaaharan do.

Chemical change mein chemical reaction ek ya zyaada naye padaarth banaati hai. Carbon dioxide se lime water ka doodhiya hona, baking soda ke saath sirke ka jhaag, lohe mein jang, magnesium ka jalna, doodh ka dahi banna aur phal ka pakna, sab chemical changes hain.

Carbon dioxide se lime water doodhiya kyun hota hai?

Lime water calcium hydroxide ka ghol hai. Carbon dioxide isse reaction karke calcium carbonate banaati hai, ek safed padaarth jo paani mein nahi ghulta, aur thoda paani. Safed baareek kan liquid ko doodhiya dikhaate hain aur baad mein neeche baith jaate hain, isliye ye carbon dioxide ki jaanch hai.

Physical aur chemical changes

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Hamaare chaaron or badlaav

Baraf pighalti hai, kaliyan khilti hain, thandi bottle garam hoti hai aur kele mein bhoore daag aur tez gandh aa jaati hai. Activity 5.1 mein tum aur badlaav likhte ho, sabzi kaatne aur paani ubaalne se lekar lakdi jalaane, geele kapde sukhaane aur aate ki loi se chapati belne tak. Har ek mein kuch badalta hai: size, aakaar, gandh, rang ya koi aur property. Hum inhe dekhkar, soonghkar, chhookar, sunkar aur chakhkar pehchaante hain. Inhe prakaar mein baantne ki shuruaat ek sawaal se hoti hai: kya is badlaav se naya padaarth bana?

Wahi padaarth, naya roop

Activity 5.2 mein kaagaz ke panne modkar naav, chidiya jaisi cheezein banao, phir kholo: wahi kaagaz hai. Gubbaara phulaao aur hawa nikaal do: wahi rubber hai. Chalk ka tukda peeso: powder ab bhi chalk hai, haalaanki use waapas chalk ka tukda nahi bana sakte. Grade 6 mein dekha tha ki paani solid, liquid ya gas ho sakta hai aur ek avastha se doosri mein badalta hai. Har baar roop badalta hai, par koi naya padaarth nahi banta. Jo badlaav sirf aakaar, size ya avastha jaisi physical properties badle, vo physical change hai.

Kaagaz modna, gubbaara phulaana, chalk peesna, aur baraf, paani aur bhaap: har baar wahi padaarth — Wahi padaarth, naya roop

Naya padaarth banta hai

Activity 5.3 mein ek tumbler ko chauthaai nal ke paani se aur doosre ko lime water se bharo, aur alag-alag straw se dono mein phoonk maaro. (Dheere phoonko, kabhi khincho mat.) Nal ka paani sirf bulbule deta hai. Lime water doodhiya ho jaata hai, aur kuch der baad neeche safed solid baith jaata hai: naya padaarth bana hai. Jo badlaav ek ya zyaada naye padaarth banaaye, vo chemical change hai, aur unhe banaane waali prakriya chemical reaction hai. Hamaari saans ki carbon dioxide lime water, yaani calcium hydroxide, ke saath reaction karke calcium carbonate banaati hai, jo paani mein nahi ghulta aur liquid ko doodhiya karta hai, aur saath mein thoda paani.

Nal ke paani mein phoonk se sirf bulbule, jabki lime water doodhiya hota hai aur safed solid baithta hai — Paani aur lime water mein phoonk

Reaction ko chhote mein chemical equation se likhte hain, shuru ke padaarth teer se pehle aur naye padaarth teer ke baad. Lime water ka doodhiya hona carbon dioxide ki maanak jaanch bhi hai.

Calcium hydroxide (lime water) + carbon dioxide → calcium carbonate (safed, na ghulne waala) + paani — Chemical equation likhna

Sirka aur baking soda

Activity 5.4 mein test tube mein thoda sirka ya nimbu ka ras daalo aur usme thoda baking soda, yaani sodium hydrogen carbonate, milao. Jhaag ki aawaaz aati hai aur gas ke bulbule dikhte hain. Ye gas taaze lime water mein le jaao to vo doodhiya ho jaata hai, isliye ye carbon dioxide hai. Naya padaarth bana, to ye bhi chemical change hai: sirka + baking soda → carbon dioxide + doosre padaarth. Test tube ki jagah do chhoti puraani bottles aur ek mudne waali straw bhi chal jaati hai. Ab yahi baking soda aur saade paani se karo: bulbule nahi bante, kyunki baking soda sirf ghulta hai, jo physical change hai.

Jang aur jalna

Lohe ko nam hawa mein chhodo to us par ek naya bhoora, parat-daar padaarth, jang, yaani iron oxide, banta hai, isliye jang lagna chemical change hai. Magnesium ribbon jalaane par chakaachaundh roshni ke saath vo safed powder, magnesium oxide, ban jaata hai, ek aur naya padaarth. Khaana pakna, doodh ka dahi banna aur phal ka pakna bhi chemical changes hain.

Chamakti lohe ki keel bhoori jang lagi keel banti hai: loha + oxygen + paani → jang (iron oxide) — Jang: naya padaarth banta hai

Dono mein fark kaise karein

Sabse pakki jaanch ye poochna hai ki naya padaarth bana ya nahi. Naya rang, gas ke bulbule, nayi gandh, liquid mein solid aana, ya garmi aur roshni nikalna chemical change ka ishaara dete hain. Physical change aksar ulta ho sakta hai, par hamesha nahi: kati sabzi kati hi rehti hai, phir bhi sabzi hi hai. Kuch prakriyaon mein dono hote hain: jalti mombatti mein wax pighalta aur vaashp banta hai, jo physical hai, aur wax ki vaashp jalti hai, jo chemical hai.

Physical aur chemical changes ki tulna: naya padaarth, kya badalta hai, kya ulta ho sakta hai, kaise likhte hain, aur udaaharan — Physical ya chemical?

Ye kyun zaroori hai

Ye jaanna ki badlaav naya padaarth banaata hai ya nahi, khaana pakaane, khaana bachaakar rakhne, jang rokne aur aag se surakshit rehne mein madad karta hai. Jalna kaise hota hai, ye combustion kya hai mein hai, aur kaunse badlaav ulte ho sakte hain, ye reversible aur irreversible changes kya hain mein. Har activity aur sawaal ke jawaab Chapter 5 ke NCERT solutions mein hain; poore Chapter 5 ke notes bhi dekho.