1. The “Basics” of Acids and Bases

2. Before Beginning Video  Reminder: Are your Acid Rain Antacid Reading Questions Done (Pages 33-34)?  Procure a Writing Utensil  Turn in Your Unit 3 Packets to Page 35

3. Acids & Bases are all around us Car batteries use concentrated sulfuric acid! Alkaline batteries use KOH (a base)

4. Acids & Bases are all around us Drano uses concentrated sodium hydroxide!

5. Acids & Bases are all around us Nair uses Calcium HydroxideHair dyes use ammonia Bases are used to break down hair!

6. Dangers of Acids & Bases  Most acids are dilute or weak enough to be fairly harmless We eat some acids  Vinegar is acetic acid  Citrus fruits contain citric acid and vitamin C (ascorbic acid) Our stomach “gastric juices” are HCl  pH can vary from 1 to 3  can get to as concentrated as 0.15M HCl

7. Dangers of Acids & Bases  Concentrated HCl – exposure to it for a minute or less if rinsed and dried thoroughly afterward will probably result in no serious effects.  Nitric Acid attacks proteins, so exposure would turn your skin yellow and cause it to peel from damage.  Sulfuric Acid – can severely burn your skin.  Hydrofluoric Acid can be fatal if breathed in or even with a small spill on your skin.

8. What is an acid or base?  Arrhenius Definition Acids dissociate in water to produce hydrogen ions HCl  H + + Cl -  Bases dissociate in water to produce hydroxide ions KOH  K + + OH -

9. What is an acid or base?  Bronsted-Lowry Definition Acids are proton donors  H + is a proton  HCl  H + + Cl -  HCl + H 2 O  Cl - + H 3 O + Bases are proton acceptors  OH - + HCl  H 2 O + Cl -  NH 3 + HNO 3  NH 4 + + NO 3 -

10. Bronsted-Lowry NH 3 C2H3O2-C2H3O2- NH 4 + CH 3 CO 2 H Arrhenius The Acid-Base Umbrella HCl HNO 3 H 2 SO 4 KOH Ba(OH) 2 NaOH

11. What about water?  Water is amphiprotic can behave as acid or base When water gives up a hydrogen ion, it is ______  Water as an acid: H 2 O + CO 3 -2  OH - + HCO 3 -  When water accepts a hydrogen ion, it is ________: Water as a base H 2 O + HCl  H 3 O + + Cl - acidic basic

12. Learning Check 1  For each rxn below, label whether water is acting an acid or base H 2 O + PO 4 -3  OH - + HPO 4 -2 H 2 O + HNO 3  NO 3 - + H 3 O + H 2 O + NH 3  OH - + NH 4 + Acid Base

13. Learning Check 1  Beside each of the following, label as AA,AB, BA, or BB Ca(OH) 2 H 2 SO 4 NH 3 HNO 3 KOH CO 3 -2 HC 2 H 3 O 2 NH 4 + So, if hydroxide is the negative ion, and it dissolves in water, it is an Arrhenius Base ! So, if hydrogen is the positive ion, and it dissolves in water, it is an Arrhenius Acid ! So, if something has a negative charge, it would probably behave as a base! AA BA AB BB AB AA

14.  Occurs when an acid and base are mixed  Hydronium (H + ) combines with hydroxide (OH - ) Neutralization Reactions

15.  If equal amounts are mixed, the final solution will no longer have properties of acid or base  Examples: When pools get too acidic, a base is added to bring up the pH levels If strong acid is spilled in lab, add baking soda Antacid is taken for a stomach ulcer

16. Neutralization Reactions  An acid-base titration is a reaction where the amount of acid needed to neutralize a base is measured  An indicator is often used to tell when neutralization has been reached. This is called the equivalence point.  The pH at which an indicator changes color is called the endpoint.  An indicator should be chosen whose endpoint is at the equivalence point for the reaction. How do I know when it is neutralized ?

17. Indicators and their Endpoints What is the endpoint for litmus? Litmus has an endpoint of 7

18. Acid-Base Titration (Neutralization)

19. Indicators and their Endpoints What is the endpoin t for phenolp hthalein ? Phenolphthalein has an endpoint of 8

20. Neutralization Reactions  Neutralization rxns are  Products are always water and a salt H 2 SO 4 (aq) + NaOH(aq)  Phosphoric Acid (aq) + Magnesium hydroxide (aq)  Double Replacement Rxns

21. Measuring the Strength of Acids  The strength of an acid is determined by the concentration of H + ions present  Strong acids completely dissociate in water, while weak acids only partially dissociate.  The higher the concentration of H + ions, the stronger the acid  Nitric, Hydrochloric, & Sulfuric Acids are strong acids

22. Measuring the Strength of Acids  The pH Scale Ranges from ___________ ___ is neutral (equal amount of H+ and OH-) pH lower than 7 = ______ pH higher than 7 = _____ The lower the pH, the __________ the acid. 1-14 7 acidic basic stronger

23. Measuring the Strength of Acids  The pH Scale pH is a measure of the concentration of H + ions pH = -log[H + ] Concentration log pH 1 x 10 -7 1 x 10 -3 1 x 10 -9 -77 -3 3 -99 Those are weird looking numbers I thought we said high H + concentrations were strong acids How can strong acids have pH of 1 if they have high H + amounts? Which one of those is the highest?