Question

rusting of nail are chemical change or physical change

Answer 1

the rusting of iron is a chemical change because it is two substance reacting together to make a new substance.

Answer 2

Rusting of nail are chemical changes.

Explanation:

• Rust is Iron Oxide, In this reaction a new substance iron oxide is formed.

        $Iron + water + oxygen ---- iron oxide (rust)$

• In this reaction the colour of the iron surfaces changes.
• Hence, rusting of iron is a chemical change.

Chemical Reaction of Rust

• The resulting chemical reaction of rusting is:

        $4Fe(s) + 3O2(g) + 6H2O(l) ------ 4Fe(OH)3(s)$

• This porous rust, Fe(OH)3(s) reacts with additional oxygen to yield a more crystallized rust with a formula of $Fe2O3. xH2O$
• The hydrated iron (III) oxide $Fe2O3$
• The causes of corrosion require the presence of water and oxygen.
• Water can combine with carbon dioxide in the air to form carbonic acid, a weak acid.

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