Practical: Determine the Formula of a Metal Oxide

Measure the mass of the crucible with the lid Add a sample of magnesium into the crucible and measure the mass with the lid (calculate the mass of the metal by subtracting the mass of the empty crucible) Strongly heat the crucible over a Bunsen burner for several minutes Lift the lid frequently to allow sufficient air into the crucible for the magnesium to fully oxidise without letting magnesium oxide smoke escape Continue heating until the mass of the crucible remains constant (maximum mass), indicating that the reaction is complete Measure the mass of the crucible and its contents (calculate the mass of metal oxide by subtracting the mass of the empty crucible)

Measure mass of the empty boiling tube Place metal oxide into a horizontal boiling tube and measure the mass again Support the tube in a horizontal position held by a clamp A steady stream of natural gas(methane) is passed over the copper(II)oxide and the excess gas is burned off The copper(II)oxide is heated strongly using a Bunsen burner Heat until metal oxide completely changes colour, meaning that all the oxygen has been removed Measure mass of the tube remaining metal powder and subtract the mass of the tube