SCIENCE
CHEMISTRY
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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heating a liquid to boiling
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dissolving a powder in water
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burning a solid
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slicing a solid into two pieces
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Detailed explanation-1: -When a firework is lit, combustion takes place leading to the formation of a new substance with the emission of light and heat. Thus, it can be considered a chemical change.
Detailed explanation-2: -The process of burning (as opposed to evaporating) is a chemical reaction, a chemical change.
Detailed explanation-3: -During burning, Carbon react with hydrogen and oxygen, turning them into Carbon dioxide ( ) and water. These changes are irreversible and ash can not be converted back to the original substance. Burning is an example of exothermic change.
Detailed explanation-4: -During combustion, the fuel reacts with oxygen to form some new gases, means a new substance is definitely formed. So, combustion is a chemical change.
Detailed explanation-5: -As we burn a paper, it changes to ash i.e. its chemical composition changes. Hence, it is a chemical change.