Mass of Wire Wool

We look at how the mass of wire wool changes when it is burned. Wire wool is almost 99% iron. When we burn it, it combines chemically with oxygen from the air to form iron(III) oxide. The mass of the product is more than the mass of the wire wool that we started with. Chemistry - Reactions - Learning Points. Combustion requires heat, oxygen and fuel. Air contains about 20% oxygen. Combustion reactions that produce gases result in lighter residues, but if no gases are lost the mass increases. In a combustion reaction, the reactant elements separate and combine with oxygen from the air to form products. A Twig Experiment Film. Let students experience real experiments in lab conditions anywhere, from setup, method all the way through to analysis and real-world application.