1. Physical and Chemical Changes

2.  Physical change- changes the form of an object without changing what type of matter it is.  Sublimation- change of state directly from a solid to a gas.

3.  Just before freezing, water molecules move farther apart and line up in a solid arrangement.  Expands and pushes on a cup

4.  Boiling point- water’s boiling point is 100 degrees celsius

5.  Thermal expansion-the increase in an object’s volume due to change in heat.  Thermal contraction-the decrease in an object’s volume due to a change in heat.  Ice is less dense than water. So water expands, instead of contracts, when it freezes This joint keeps the bridge from breaking or buckling on hot days

6.  Mixture- a physical combination of substances. The substances remain the same.  Colloid- a mixture like a suspension, except that its parts do not settle. The particles are just small enough not to layer out.  Mayonnaise, foam- examples of colloids

7.  Solution- mixture with parts that blend so that it looks the same everywhere.  Example: sugar into water, bleach  Solute- substance that is dissolved (sugar)

8.  Compound- formed by the combination of two or more elements.  Iron Oxide= 2 iron atoms and 3 oxygen atoms

9.  Chemical Reaction- atoms link to create a new substance. Example- baking soda, vinegar.  Chemical Equations- left side is the chemicals that combine (reactants). Right side is the new substance (product). Total mass is equal

10.  Plants- create food using photosynthesis ( a chemical reaction), simple sugars

11.  Acids- dissolve in water, taste sour, turn blue litmus to red, help digest food, used to clean steel and plastics.  Base- turns red litmus paper blue, can clear clogged drains, used to make fertilizers, used to make cloth, soaps, and some plastics.

12.  Neutralization- when acids and bases react to form salt and water.  Electrolyte- a substance that forms ions in water.  Found in sports drinks