Are these materials cool or hot? Why?

All the materials are hot. The primary material which comes out of a volcano is lava. It is extremely hot and molten in the state. All other materials which come out of a volcano like steam gases, gaseous sulphur compounds and broken pieces of rocks are also very hot and have a heat radiating effect to long distance.

The temperature of the erupted or ejected materials is very high because deep within the earth it is so hot that some rocks melt and slowly becomes a thick flowing substance called magma.