Ima

Definition:A chemical reaction is a process in which one or more substances change into new substances with different properties.

Examples:

• Rusting of iron: Iron + oxygen + water → rust

• Burning of wood: Wood changes into ash, gases, and heat.

• Cooking an egg: The egg changes and cannot be changed back.

Signs that a chemical reaction has happened:

• Colour change

• Temperature change (heat released or absorbed)

• Gas is produced (bubbles)

• A new solid (precipitate) forms

• Light or smell is produced

Why is it related to materials and their properties?

Chemical reactions can change:

• Colour

• Hardness

• Strength

• Ability to conduct electricity

• Other properties of the material

So, "Chemical Reactions and Ch