Which process involves the transformation of substances resulting in new products?

The process that involves the transformation of substances resulting in new products is known as a chemical reaction. In a chemical reaction, the atoms of the original substances rearrange, forming new substances with different properties. For instance, when iron reacts with oxygen, it produces rust, which is a new substance consisting of iron oxide.

This transformation distinguishes chemical reactions from other processes like physical changes, where the substance may change in state or appearance but the molecular structure remains the same; phase changes, which refer specifically to transitions between solid, liquid, and gas states without altering the chemical identity; and mechanical mixing, where substances are combined but retain their individual properties and identities without forming new products.