Answer:
The chemical weathering refers to the disintegration or erosion of rocks due to chemical activities, mainly with the help of water and the components dissolved in it. On the other hand, the procedure of dissociating large rocks into smaller ones is known as mechanical weathering. In this kind of weathering temperature plays an essential role. The hot days and cool nights always make the things to contract and expand, this process can make the rocks to dissociate and break apart.
Thus, in the Congolese rainforest, which is hot and humid, the rates of chemical weathering will be more here in comparison to the conditions in Siberia. While on the Siberian steppes the rates of mechanical weathering will be more because of thawing and freezing conditions.