1. Chemical Reactions When substances change into new substances!

2. Components of the Chemical Reaction hydrogen (g) + oxygen (g)  water (l) reactants  products 2 H 2 (g) + O 2 (g)  2 H 2 O (l) coefficient # of atoms the state (liquid)

3. Four Types of Reactions  Synthesis  Decomposition  Single Displacement  Double Displacement

4. Synthesis Reaction  Involves the combination of two or more simple substances to form a more complex substance

5. Combustion Reactions  Synthesis reactions where oxygen is one of the reactants.  An element reacts quickly with oxygen gas to form more complex compounds by burning  Example: C (s) + O 2 (g)  CO 2 (g)

6. Decomposition Reactions  Involve the breakdown of large, complex molecules or ionic compounds into smaller simpler entities.  Usually involve the presence of heat or a catalyst.

7. Single Displacement  A reaction with an element and a compound that results in a new element and a new compound.  In order to tell whether or not a single displacement reaction has occurred, you need the ACTIVITY SERIES

8. The Activity Series  A metal above (or left) will displace the metal below (or right)  Metals before Hydrogen will react with acid. Metals after Hydrogen will not react with acid.  The first five metals will react with water.

9. Double Displacement Reactions  This reactions always involves ionic compounds.  The cation of one compound changes place with the cation of the other compound.  This reaction can produce water, a gas or a precipitate.

10. Reactions That Produce a Precipitate  Precipitate: a solid formed as a result of a chemical reaction between two aqueous solutions  You need to know the solubility rules in order to predict whether or not a precipitate forms.

11. Solubility Rules

12. Predicting Precipitate Formation  Step 1: Identify type of reaction and possible products  Step 2: Look up solubility of both products  Step 3: Indicate states of reactants and products  Step 4: Write chemical equation for reaction  Step 5: Balance equation

13. Practice!  Identify the product for each reaction  Classify each of the following reactions  Write the chemical formula for each species  Write the balanced equation a. magnesium (s) + oxygen (g)  b. iron (s) + copper (II) sulfate (aq)  c. nitrogen trihydride (g)  d. potassium iodide (aq) + lead (II) nitrate (aq) 