How is rock breaking down into small pieces different from a fence rusting? use chemical and mechanical weathering to help explain your answer.

Rusting is a chemical change while breaking down of ricks may just be due to mechanical weathering of rocks

Explanation:

Rusting is a chemical reaction. Rust refers to hydrated iron III oxide. This substance is soft and flakes easily hence making the iron soft and brittle. The entire process of rusting is an electrochemical reaction set up with water as the electrolyte.

Mechanical weathering is the process of breaking big rocks into smaller pieces. The process usually occurs near the surface of the earth. The cool nights and hot days always cause rocks to expand and contract. This movement can cause rocks to crack and break apart. The entire process is a physical process.

Hence rusting makes iron brittle and flake by a chemical process while mechanical weathering break rocks in pieces by a physical process.

the dissolution of polymer can be thermodynamically described in 2 steps.