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What is Chemical Change......?What is it, how do you know its happening and how is it...

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lazyjelly | Student, Grade 9 | (Level 2) eNoter

Posted October 9, 2012 at 6:04 AM via web

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What is Chemical Change......?

What is it, how do you know its happening and how is it diffrent to physical change

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minjoo98 | Student, Grade 9 | (Level 1) eNoter

Posted October 9, 2012 at 10:29 AM (Answer #1)

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Chemical change is when a different, new substance is formed. Example of this is burning paper. Paper became another substance, ash. Physical change considers states of matter and energy. Physical change is like curshing a bottle, melting ice, or freezing ice.If a matter changes into another state of matter (like water becomes ice or gas) it is physical change. Chemical change is only when molecules are changed. Clues that chemical change took place :light, heat, color change, gas production, odor, or sound. I hope this helps...:)

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loraaa | Student | (Level 2) Valedictorian

Posted October 9, 2012 at 12:38 PM (Answer #2)

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Chemical Changes
Chemical changes take place on the molecular level. A chemical change produces a new substance.

Physical Changes
Physical changes are concerned with energy and states of matter. A physical change does not produce a new substance.

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sanjeetmanna | College Teacher | (Level 3) Assistant Educator

Posted October 9, 2012 at 1:11 PM (Answer #3)

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When a egg is cooked, liquid protein form is converted into solid form and it is irreversible this is called chemical change.

Chemical change is a change where a new substance is formed which occur at molecular level by formation of bond or breaking of bond and which is irreversible.

A chemical change can be a exothermic or endothermic depending upon the type of the reaction. If heat is produced then it is exothermic and if heat is required for the reaction then it is called endothermic.

Example: - Digestion of food, burning of gasoline, burning of wood, photosynthesis, making food, ripening of fruits, burning of magnesium strips.

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