Chemistry / रसायन विज्ञान
The source defines Chemistry as a branch of physical science dealing with the composition, properties and behaviour of matter.
Chemistry physical science की branch है जिसमें matter की composition, properties तथा behaviour का study किया जाता है।
Physical Changes / भौतिक परिवर्तन
Physical changes affect physical properties such as colour, hardness, density and melting point without changing the composition and chemical properties of matter.
Physical Change में colour, hardness, density, melting point जैसी physical properties change हो सकती हैं, लेकिन matter की composition तथा chemical properties change नहीं होतीं।
The source characterises physical changes as temporary.
Examples / उदाहरण
- Crystallisation / Crystallisation
- Sublimation / Sublimation
- Boiling / Boiling
- Melting / Melting
- Vaporisation / Vaporisation
- Cutting of trees / Trees काटना
- Dissolving sugar or salt in water / Water में sugar या salt dissolve करना
Chemical Changes / रासायनिक परिवर्तन
Chemical changes affect the composition and chemical properties of matter and result in formation of a new substance.
Chemical Change में composition तथा chemical properties change होती हैं और new substance form होता है।
The source characterises chemical changes as permanent.
Examples / उदाहरण
- Burning of fuel / Fuel का burning
- Burning of candle and paper / Candle और paper का burning
- Electrolysis of water / Water का electrolysis
- Photosynthesis / Photosynthesis
- Ripening of fruits / Fruits का ripening
Matter / पदार्थ
Anything that occupies space and has mass is called matter.
जो भी space occupy करता है तथा mass रखता है उसे Matter कहते हैं।
States of Matter / पदार्थ की अवस्थाएँ
- Solid / ठोस
- Liquid / द्रव
- Gas / गैस
The source additionally discusses Plasma and Bose-Einstein Condensate or BEC.
Plasma / प्लाज्मा
The source describes plasma as ionised gases containing highly energetic and excited particles.
Bose-Einstein Condensate / बोस-आइंस्टीन संघनन
The source describes BEC as a gas at extremely low temperature and extremely low density.
Boiling Point / क्वथनांक
The temperature at which a liquid converts into vapour is called its boiling point.
जिस temperature पर liquid vapour में convert होता है उसे Boiling Point कहते हैं।
- Boiling point of water → 100°C
- Source states that impurities increase boiling point.
- At high altitude, boiling point decreases.
- Therefore food takes more time to cook at high altitude according to the source.
Melting Point / गलनांक
The temperature at which a substance changes from solid to liquid is called melting point.
जिस temperature पर solid substance liquid में convert होता है उसे Melting Point कहते हैं।
- Melting point of ice → 0°C
- The source states that impurities decrease the melting point.