3. pH less than 7 Neutralizes bases Forms H + ions in solution Corrosive-reacts with most metals to form hydrogen gas Good conductors of electricity

4. HNO 3 + H 2 O  H 3 O + + NO 3

5. HCl- hydrochloric- stomach acid H 2 SO 4 - sulfuric acid - car batteries HNO 3 – nitric acid - explosives HC 2 H 3 O 2 - acetic acid - vinegar H 2 CO 3 -carbonic acid – sodas H 3 PO 4 - phosphoric acid -flavorings

6.  Strong Acids are Strong Electrolytes  They dissociate completely in water.  100% of the HA molecules break up into H+ and A- ions.  There are six common strong acids chemists MUST know: 1. HCl- Hydrochloric Acid 2. HI- Hydroiodic Acid 3. HBr- Hydrobromic Acid 4. HNO 3 - Nitric Acid 5. HClO 3 - Chloric Acid 6. H 2 SO 4 - Sulfuric Acid *1st dissociation only

7.  Weak Acids are Weak Electrolytes  They DO NOT dissociate completely in water.  1% of the HA molecules break up into H+ and A- ions.  There are five common weak acids chemists MUST know: 1. HF- Hydrofluoric Acid 2. H 3 PO 4 - Phosphoric Acid *1st dissociation only 3. HC 2 H 3 O 2 - Acetic Acid 4. H 3 BO 3 - Boric Acid *1st dissociation only 5. C 6 H 8 O 7 - Citric Acid

8.  pH greater than 7  Feels slippery  Dissolves fats and oils  Usually forms OH - ions in solution  Neutralizes acids

9.  NaOH- sodium hydroxide (LYE) soaps, drain cleaner  Mg (OH) 2 - magnesium hydroxide-antacids  Al(OH) 3 -aluminum hydroxide-antacids, deodorants  NH 4 OH-ammonium hydroxide- “ammonia”

10.  Strong Bases are Strong Electrolytes  They dissociate completely in water.  100% of the BOH molecules break up into B+ and OH- ions.  There are eight common strong bases chemists MUST know: 1. KOH- Potassium Hydroxide 2. NaOH- Sodium Hydroxide 3. LiOH- Lithium Hydroxide 4. CsOH- Cesium Hydroxide 5. RbOH- Rubidium Hydroxide 6. Ba(OH) 2 - Barium Hydroxide 7. Ca(OH) 2 - Calcium Hydroxide 8. Sr(OH) 2 - Strontium Hydroxide

11.  Weak Bases are Weak Electrolytes  They DO NOT dissociate completely in water.  1% of the BOH molecules break up into B+ and OH- ions.  There are six common weak bases chemists MUST know: 1. NH 3 - Ammonia 2. C 5 H 5 N- Pyridine 3. CH 3 NH 2 - Methylamine 4. C 3 H 5 O 2 NH 2 - Alanine 5. Be(OH) 2 - Beryllium Hydroxide 6. Mg(OH) 2 - Magnesium Hydroxide

12.  In the 1800’s chemical concepts were based on the reactions of aqueous solutions.  Svante Arrhenius developed a concept of acids and bases relevant to reactions in H 2 O.  Arrhenius acid – produces hydrogen ions in water.  Arrhenius base – produce hydroxide ions in water.

13. A broader,more modern concept of acids and bases was developed later. Bronsted-Lowry acid- donates a hydrogen ion in a reaction. Bronsted – Lowry base – accepts a hydrogen in a reaction.

14.  Conjugate acid- compound formed when an base gains a hydrogen ion.  Conjugate base – compound formed when an acid loses a hydrogen ion.

15.  Acids can be classified by how many H+ ions per molecule are given.  Monoprotic acids  Diprotic acids  Polyprotic acids  Ex: H 2 SO 4(aq) + H 2 O H 3 O + + HSO 4 - (aq) HSO 4 - (aq) + H 2 O H3O + + SO 4 2- (aq)

16.  Proton Transfer  This occurs in every acid-base reaction.  When acids and bases react, a proton is transferred from the acid to the base.  This is the driving force of acid-base reactions.  Once the proton is transferred, it is in a position of less chemical potential.  Formation of water  If the acid contains H + and the base contains OH - the acid base reaction will form water.  The remaining cation and anion form a salt.  If both the acid and base are weak, no reaction occurs because no ions are present to initiate the proton transfer.

17.  HCl + H 2 0  H 3 O + + Cl - (more hydronium ions, more acidic)  NaOH in water  Na + + OH - (more hydroxide ions, more basic)  NaOH + HCl  NaCl + HOH Acid + Base yields type of salt and water  NH 3 + H 2 0  NH 4 + + OH - ammonia gas + water yields ammonium and hydroxide ions

18.  Acid-Base Reactions are also called Neutralization Reactions  Acids and Bases are extremely corrosive materials.  This means that they destroy things they come into contact with, including skin, plant tissue, and even metals when the acid or base is strong enough.  For this reason, chemists should be VERY careful when handling them.  When acid-base reactions occur, corrosive materials become harmless materials (water and salt).  Another way to say this is to say that they are neutralized.

19.  Consider the reaction between nitric acid and potassium hydroxide.  Molecular Equation HNO 3 ( aq ) + KOH( aq )  KNO 3 ( aq ) + H 2 O( l )  Complete Ionic Equation – both acid & base dissociate. H + ( aq ) + NO 3 - ( aq ) + K + ( aq ) + OH - ( aq )  K + ( aq ) + NO 3 - ( aq ) + H 2 O( l )  Net Ionic Equation – always shows formation of water. H + ( aq ) + OH - ( aq )  H 2 O( l )

20.  Consider the reaction between acetic acid and sodium hydroxide.  Molecular Equation HC 2 H 3 O 2 ( aq ) + NaOH( aq )  NaC 2 H 3 O 2 ( aq ) + H 2 O( l )  Complete Ionic Equation – only the base dissociates. HC 2 H 3 O 2 ( aq ) + Na + ( aq ) + OH - ( aq )  Na + ( aq ) + C 2 H 3 O 2 - ( aq ) + H 2 O( l )  Net Ionic Equation HC 2 H 3 O 2 ( aq ) + OH - ( aq )  H 2 O( l ) + C 2 H 3 O 2 - ( aq )

21.  Consider the reaction between hydrochloric acid and ammonia.  Molecular Equation HCl( aq ) + NH 3 ( aq )  NH 4 + ( aq ) + Cl - ( aq )  Complete Ionic Equation – only the acid dissociates. H + ( aq ) + Cl - ( aq ) + NH 3 ( aq )  NH 4 + ( aq ) + Cl - ( aq )  Net Ionic Equation H + ( aq ) + NH 3 ( aq )  NH 4 + ( aq )

23. pH of Common Substances Timberlake, Chemistry 7 th Edition, page 335

25. IndicatorAcid color Neutral color Base color PhenolphthaleinColorlessFaint pinkDark pink Bromthymol blue YellowGreenBlue LitmusRed-----Blue

26.  pH paper changes color to indicate a specific pH value.

27.  A buffer is a solution that resists changes in pH when small amounts of acids and bases are added.

28.  “Heartburn”  Planting vegetables and flowers  Fish Tanks and Ponds  Blood  Swimming pools

29. Pollution in the air (sulfur dioxide, carbon dioxide, nitrogen dioxide) combines with water to form various acids..

30. Rapid changes in pH can kill fish and other organisms in lakes and streams. Soil pH is affected and can kill plants and create sinkholes