Chemical Changes

Physical Change Ice melting Sharpened pencil Matter changes in size , shape , or state with out changing identity . Can be reversed Example: Ice melting Sharpened pencil

3 examples of physical changes are... piece of paper is cut up into small pieces This would be a physical change in the shape and size of the paper .

Mix salt into water to create saltwater. this would be a physical change as the water could be left out to evaporate and the salt crystals would remain

Changing ice into water For example, a cup of water can be frozen when cooled and then can be returned to a liquid form when heated

Chemical Change burnt toast Rusty nail Tarnished silver Chemical changes occur when atoms link together to cause new compounds to form a new substance burnt toast Rusty nail Tarnished silver

What are the 3 signs of chemical changes? Color change Formation of light and heat Formation of gas

Reactamts An original substance at the beginning of a chemical change Example : ingredients to bake a cookies

Products A new substance produced by a chemical change Example: Cookies are produced After you mix all the ingredients and bake it

Example of a chemical change Baking a cake Reactants flour, water, sugar and other ingredients mixed together The cake Product

Why are chemical changes harder to reverse than physical? In a chemical change a new substance is formed and physical change only changes in appearance