GK
CHEMISTRY
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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Change in color
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Change in shape
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melting
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vaporizing
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Detailed explanation-1: -Some signs of a chemical change are a change in color and the formation of bubbles. The five conditions of chemical change: color change, formation of a precipitate, formation of a gas, odor change, temperature change.
Detailed explanation-2: -A pH or acid-base indicator is a compound that changes color depending on the pH of the substance that is added to it. Acids and bases make pH indicators turn different colors.
Detailed explanation-3: -The color changes which occur in chemical reactions are caused by the production of products which can absorb energy to emit visible colors because of the electronic transitions occurring upon the absorption of energy. Electronic transition refers to the movement of electrons from one energy level to another.