Physical and Chemical Changes

Physical Properties Any characteristic of a material that you can observe without changing the substances that make up the material EX: shape, size, texture, phase of matter, density, BP, MP

change in the size, shape, or state of matter Physical Change change in the size, shape, or state of matter EX: melting iron, water freezing, crumpling paper, smashing a rock

Chemical Properties A characteristic of a substance that indicates whether it can undergo a certain chemical change EX: Flammability, radioactivity, new substances can be formed

A change of one substance in a material to a different substance Chemical Change A change of one substance in a material to a different substance EX: foaming of antacid tablet What in the picture is chemically changing?

Chemical Reactions When a chemical reaction occurs, there is always a change in the properties and energy content of the substances involved. There is a change in both the physical and chemical properties as substances are changed into new substances. Most of the time, at least one of the following will be obvious when a chemical reaction takes place:

6 indications of a chemical change 1. Color change 2. precipitate - cloudy 3. formation on light 4. heat given off 5. gas given off – bubbles/ fizzes 6. new substance with new properties

Phase Change The physical change of matter from one phase to another. A phase change takes place because the particles of a substance gain or lose energy, causing them to change their motion

Names for phase changes Melting - Solid changes to Liquid Freezing - Liquid changes to Solid Sublimation - Solid changes to Gas Snow - Gas changes to Solid Vaporization - Liquid changes to Gas Evaporation - vaporization that takes place at the surface of a liquid. Condensation - Gas to Liquid

Draw the following graph into your notes:

Boiling Point Temperature The temperature at which a liquid boils Water boils at 100 oC, 212 oF Table salt boils at 1413 oC Diamond boils at 4200 oC

Freezing Point Temperature The temperature at which a liquid changes to a solid Water freezes at 0 oC, 32 oF Table salt freezes at 801 oC Diamond freezes at 3700 oC

Melting Point Temperature The temperature at which a solid changes to a liquid Water (ice) melts at 0 oC, 32 oF Table salt melts at 801 oC Diamond melts at 3700 oC

LAW OF CONSERVATION OF MATTER & ENERGY States that Mass cannot be created or destroyed only conserved IT ONLY CHANGES FORMS 

Law of Conservation of Mass