* Formation of Copper Oxide: When copper is heated in the presence of oxygen (from the air), it reacts with the oxygen to form copper oxide.
* Color Change: Copper oxide has a black color, hence the change in appearance.
* New Substance: Copper oxide is a different substance from copper. This means a chemical transformation has occurred, not just a physical change like melting or freezing.
The Chemical Equation:
The reaction can be represented by the following chemical equation:
2 Cu (s) + O₂ (g) → 2 CuO (s)
Where:
* Cu = Copper
* O₂ = Oxygen
* CuO = Copper oxide
Key Points:
* Chemical reactions involve the formation of new substances with different properties.
* In this case, the heat provides the energy needed for the copper and oxygen atoms to bond and form copper oxide.
