1. Chemical Reactions

2. Chemical Reaction  A process in which one or more substances are converted into new substances with different physical and chemical properties

3. Chemical Equations Mg + S  MgS Reactants – the elements/compounds on the LEFT side of the equation Products – the elements/compounds on the RIGHT side of the equation  - means “yields” or “produces”

4. Two way to write equations: 1. Word Equations Ex: magnesium reacts with sulfur to produce magnesium sulfide 2. Formula Equations Ex: Mg + S  MgS

5. Diatomic Molecules There are 7 elements on the periodic table that cannot exist alone. They will pair up with each other in order be stable. Those elements are:

6. If it says:Write: HydrogenH2H2 OxygenO2O2 NitrogenN2N2 FluorineF2F2 ChlorineCl 2 IodineI2I2 BromineBr 2

7. Word Equations with Diatomics When given a word equation with one of those seven elements (only if they are an element), you will use the diatomic form in the formula equation. Ex: sodium reacts with oxygen Na + O 2 not Na + O

8. Write the formula equation for the following word equation:  Oxygen reacts with sodium fluoride to produce sodium oxide and fluorine  O 2 + NaF  Na 2 O + F 2

9. Law of Conservation of Matter States that matter is not created nor destroyed Mass of Reactants = Mass of Products

10. Balancing Equations You must make sure there are the SAME NUMBER of each element on both sides of the equation Ex: 2Na + Br 2  2NaBr Coefficients – the numbers used to balance an equation

11. Balance the following:  K + MgI 2  KI + Mg  2K + MgI 2  2KI + Mg  Ca(OH) 2 + HCl  CaCl 2 + H 2 O  Ca(OH) 2 + 2HCl  CaCl 2 + 2H 2 O