2. Types of Chemical Reactions Synthesis Two or more substances form one new substance A + B  AB H2+O2H2OH2+O2H2O N 2 +H 2  NH 3

3. Types of Chem Rxns – cont’d Decomposition One substance breaks down to form two or more new substances AB  A + B PbCO 3  PbO+CO 2 H 2 CO 3  H 2 O+CO 2

4. Types of Chem Rxns – cont’d Single Displacement One substance replaces another in a compound A + BC  B + AC Li+AlCl 3  LiCl+Al

5. Types of Chem Rxns – cont’d Double Displacement Two substances “swap partners” in two compounds AB + CD  AD + CB KOH+HBr  KBr+H 2 O NaOH + H 2 CO 3  Na 2 CO 3 + H 2 O

6. Types of Chem Rxns – cont’d Neutralization [Acid / Base] Double-displacement reaction where an acid and a base form a chemical “salt” and water KOH+HBr  KBr+H 2 O NaOH + H 2 CO 3  Na 2 CO 3 + H 2 O

7. Review – Acids & Bases Acids - General Characteristics Taste Sour Have a pH of less than 7 Produce Hydronium H 3 O +1 in solution Have an “extra” H- on the beginning of the formula H 2 SO 4 – (Hydro)Sulfuric Acid H 3 PO 4 – (Hydro)Phosphoric Acid HNO 3 – (Hydro)Nitric Acid HCl – Hydrochloric Acid

8. Review – Acids & Bases Bases - General Characteristics Taste bitter Have a pH of more than 7 Produce Hydroxide OH –1 in solution Have an –OH on the end of the formula NaOH – Sodium Hydroxide KOH – Potassium Hydroxide Ca(OH) 2 – Calcium Hydroxide NH 4 OH – Ammonium Hydroxide

9. Types of Chem Rxns – cont’d Combustion Carbon compound combusts with oxygen gas to form carbon dioxide and water CH 4 + O 2  CO 2 + H 2 O C 2 H 6 + O 2  CO 2 + H 2 O

10. Discuss In which two types of reactions do you find water as a product? ---------------------------------- On-Level – on page 6 [Chembalancer w/s], complete the “type of reaction” for #s 1-11. Honors – check your answers to Chembalancer “type of reaction” pages mid6-top8.

11. Chembalancer Activity Answers 1-11 1. synthesis7. combustion 2. synthesis 8. double displacement 3. synthesis 9. synthesis 4. synthesis 10. synthesis 5. decomposition 11. decomposition 6. single displacement

12. Activation Energy Some reactions require a little “jump start” to proceed Activation Energy Energy required to be applied to start a reaction amount of energy from starting point [reactants] to top of reaction curve Examples Applying friction to start a match The match causing a log to burn

13. Activation Energy – cont’d Hydrogen + Oxygen  Water Hydrogen [gas] Oxygen [gas] Water [liquid] Activation Energy

14. Changes in Energy Every reaction has a change in energy Endothermic – absorbs energy from the environment to complete reaction Feels “COLD” to its surroundings Products have MORE energy than the reactants

15. Changes in Energy – cont’d Endothermic vs. Endergonic Endothermic requires heat Endergonic requires energy

16. Changes in Energy – cont’d Every reaction has a change in energy Exothermic – releases energy to the environment as the reaction proceeds Feels “HOT” to its surroundings Products have LESS energy than reactants

17. Changes in Energy – cont’d Exothermic vs. Exergonic Exothermic gives off heat Exoergonic gives off energy ~End~

18. Homework complete worksheets: Types of Chemical Reactions [pg10 - top11] Classifying Chemical Reactions [pg 11]