Which of the following observations is/are examples of chemical change?
1) Iron (Fe) rusts,forming Fe₂O₃.
2) The density of water increases when it changes from a solid to a liquid.
3) Sodium chloride melts at 801 $^{\circ}$ C.

Question

Which of the following observations is/are examples of chemical change?
1) Iron (Fe) rusts,forming Fe₂O₃.
2) The density of water increases when it changes from a solid to a liquid.
3) Sodium chloride melts at 801

^{\circ}

C.

Quizplus · Accepted Answer

Observation 1 involves a chemical change, as iron (Fe) reacts with oxygen (O) to form rust (Fe₂O₃). Observation 2 is a physical change, as the density of water changes due to a phase transition from solid to liquid. Observation 3 is also a physical change, as sodium chloride (NaCl) undergoes a phase transition from solid to liquid at a specific temperature.

Which of the Following Observations Is/are Examples of Chemical Change ∘^{\circ}∘

Which of the Following Observations Is/are Examples of Chemical Change $^{\circ}$