Question

How can we tell if a change has resulted in a chemical reaction?​

Answer 1

Answer:

If the properties of the reactant has changed we can that it is a chemical reaction

Explanation:

During a chemical reaction the reactant under goes some chemical changes and it's chemical properties get changed.

Therefore we can say that if the chemical properties of the reactant before the reaction are different than it's chemical properties after the reaction we can say that the substance has undergone through chemical reaction.

Example,

When iron kept in open undergoes through reaction with water vapour and oxygen present in air, formation of a brown coating takes place on the surface of iron.This brown coating is called rust. Here the properties of the surface of iron (reactant) have changed .

Therefore it is a chemical reaction.

This reaction can be represented as follows:

Fe (iron). +H2O(water vapour). +O2(oxygen) gives = Fe2O3•32H2O(Rust)

(solid) (gas). (gas). Solid