1. Smelting

2. Chemistry in history The Stone, Bronze, and Iron Ages are historical periods named after the most common material that was used for making tools during each time. The Bronze Ages came before the Iron Age because copper and tin, the elements that are melted together to form the alloy bronze, were both widely available and easily accessible metals. Bronze is stronger than either copper or tin alone. The Iron Age came later because iron is harder to reduce to elemental form. It requires smelting at a higher temperature than bronze

3. How can we start it? Limestone CaCO3 which is mixed with the iron ore in the furnace It is a decomposition reaction In this process,it'll produce CO2 and CaO CaCO3(s)→CaO(s)+CO2(g)

4. It's time to get our reducing agent! CO2(g)+C(s)→2CO （ g ） The carbon dioxide(produced by CaCO3 ) oxidize the coke to form carbon monoxide, which is used to reduce the iron ore to iron. It is a redox reaction In the process, carbon is oxidized and it is reducing agent Carbon dioxide is reduced and it is oxidizing agent

5. Then we’ll get Iron Fe2O3+3CO=2Fe+3CO2 Iron ore(Fe2O3) is reduced by carbon monoxide during this reaction. The product is iron and carbon dioxide. The reason we do not use carbon to reduce iron ore directly is that carbon is solid. It is not easy to make carbon react with iron ore, which is also solid. Additionally, Fe3O4 is a possible substitute for Fe2O3.

6. Considering about R&O CaCO3(s)→CaO(s)+CO2 （ g ） Ca:+2→+2 O:-2→-2 CO2 （ g ） +C （ s ） →2CO （ g ） C ： +4→+2 anotherC ： 0→+2 O ： -2→-2 Fe2O3+3CO=2Fe+3CO2 Fe:+3→0 O ： -2→-2 C ： +2→+4