When you burned copper, the product copper oxide appeared on the wire. Besides copper, the other reactant is
air
⇒ oxygen, O2.
Explain how you know it must be oxygen. Where did the oxygen come from?

2b2t

explanation:

2b2t

definition

                    entropy is a measure of the randomness or the extent of disorder of a chemical process.

                      enthalpy is a measure of the heat change of a reaction occurring at a constant pressure.

measurement units:

                        entropy is measured in joule per kelvin (jk⁻¹)   whereas enthalpy is measured in joule per mole (jmol⁻¹)

requirements:

                            entropy has no requirements or limits, and its change is measured by the division between the heat change of the chemical process and the temperature.

                              in contrast, enthalpy can only be related to the heat change of the reaction under standard conditions.