Question

Oxides of which elements can be reduced by heating only

Answer 1

yes oxides are heated alone to give pure metal for example cinnabar hgo when heated gives hg +so2

Answer 2

Metals such as zinc, iron and copper are present in ores as their oxides. Each of these oxides is heated with carbon to obtain the metal. The metal oxide loses oxygen, and is therefore reduced. The carbon gains oxygen, and is therefore oxidised.