Thursday, March 24, 2011

Differentiate between chemical and physical changes

Grind chalk-Cut paper into pieces -dissolve sodium chloride salt in water -pulverize sugar crystals ......
Do you observe change in color ?
Do you smell anything ?
Do yo see effervesence of gas?
Is the container turning hot ?
Can you see light  formed ?
Al these changes are physical changes as no new substances are formed .
Add lemon to chalk-burn sugar on fire -burn a piece of paper -put baking powder and vinegar......

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