SSC
CHEMISTRY
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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it isn’t
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it creates a new substance
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it uses the law of conservation of mass
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it has energy
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Detailed explanation-1: -The rusting of iron is a chemical change because it is two substances reacting together to make a new substance. When iron rusts, iron molecules react with oxygen molecules to make a compound called iron oxide. Rusting would only be a physical change if iron molecules remained pure iron throughout the process.
Detailed explanation-2: -The interaction of Iron with air and water produces rust. The Oxygen present in the air form a powdered substance called rust. The rust is a red-orange flaky substance and the phenomenon of the formation of rust is called rusting.
Detailed explanation-3: -Rust is a result of chemical reaction where iron gets oxidized in presence of oxygen and moisture to form iron oxide. The chemical reaction for rusting is: 4Fe + 3O2 → 2Fe2O3. Iron is first oxidized to iron(II) ions by oxygen.