A match is lit and held under a cold piece of metal. The following observation are made. A) the match burnsB) the metal gets warmerC) water condenses on the metalD) soot (carbon) is deposited on the metal. Which of these occurrences are due to physical changes and which are due chemical changes?

A - chemical changes

B - Physical changes

C - Chemical changes

D - Chemical changes

Explanation:

First and foremost, a chemical change is an irreversible change in the chemical properties of a substance leading to the formation of a new substance or substances while a physical change is a reversible change to the properties of a substance.

The burning of a match stick is an irreversible process involving the reaction of the various component of the match head (potassium chlorate, sulfur, glass powder) with that of the side of the box holding the match (phosphorus, binder, glass powder). Hence, it is considered a chemical reaction.

Warming of the metal is a reversible process and hence, a physical reaction. Warming involves a rise in temperature due to the heating. Once the heat source is removed and the metal allowed to stay for a while, its temperature will return back to the original temperature.

Water condensation and deposition of soot on the metal can be considered a chemical reaction. A reaction that leads to the formation of, at least, one new product is definitely a chemical reaction.

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