Question

A match is lit and held under a cold piece of metal. The following observations are made: (a) The match burns. (b) The metal gets warmer. (c) Water condenses on the metal. (d) Soot (carbon) is deposited on the metal. Which of these occurrences are due to physical changes, and which are due to chemical changes?

Short answer

In the given scenario, the physical changes are (b) the metal getting warmer and (c) water condensing on the metal, as they do not involve changes in the chemical composition. The chemical changes are (a) the match burning and (d) soot (carbon) being deposited on the metal, as they involve changes in the chemical composition.

Step-by-step solution

(Step 1: Identify physical changes)

(In the given observations, the warming up of the metal and the water condensation can be considered as physical changes. These changes did not involve any modification of the chemical composition of the substance (metal).)

(Step 2: Identify chemical changes)

(In the given observations, the match burning and the soot (carbon) deposition can be considered as chemical changes. These changes involve a change in the chemical composition - the match undergoes combustion, and carbon is deposited on the metal surface.)

(Step 3: Summarize the results)

(To conclude, the following physical and chemical changes were observed: - Physical changes: (b) The metal gets warmer and (c) Water condenses on the metal. - Chemical changes: (a) The match burns and (d) Soot (carbon) is deposited on the metal.)