1. Physical Change A change that alters the form or appearance of a substance but does NOT make the material into another substance –Example: ripping paper, melting ice

2. Chemical Change A change in matter that produces new substances. –Example: burning paper, mixing chemicals (alka seltzer and water)

3. Solutions Solution = a well mixed mixture having the same properties throughout. –Example salt water

4. Solutions Uniform mixture = an evenly mixed solution Solvent = substance that dissolves another substance Solute = what is being dissolved –May change phase –Usually the smaller amount

5. Solutions Soluble = if a substance will dissolve in another substance it is soluble Insoluble = if a substance will NOT dissolve it is called insoluble Dilute = weak solution, lots of solvent, little solute Concentrated = strong solution, lots of solute, little solvent Saturated = when no more solution can be dissolved in the solvent

6. Acids and Bases Acids – Compounds begin with H –Example: Citric Acid, HCl, H 2 SO 4 Turns Litmus paper Red or Pink Examples: Lemon juice, Orange Juice Tastes sour Bases – Compounds end in OH Example: NaOH, KOH Turns Litmus paper Blue Examples: Soap, Ammonia Tastes bitter, feels slippery

7. Indicators and pH Indicator = something that turns color in the presence of a certain substance pH scale = a chart of acidity and basicity that goes from 1 to 14

8. pH Scale 12 3 4 5 6 7 8 9 10 11 12 13 14 Strongweak neutral weak strong Acidacid basebase Neutralization reaction: when an acid and base combine. It forms salt and water. Ex: HCl + NaOH ->H 2 O + NaCl acid base water salt

9. Chemical Reactions Chemical reaction = a process in which substances undergo chemical changes All chemical reactions either take in or give off energy. The energy is usually in the form of heat. –Endothermic reaction: a reaction that ABSORBS energy in the form of heat. –Exothermic reaction: a reaction that RELEASES energy in the form of heat.