1. ACIDS AND BASES Chapter 13-14

2. If one has an ionic compound and puts it into water, the compound will break into two ions. If one of those ions is H+, the solution is acidic. If one of the ions is OH- the solution is basic. Ions determine whether the substance is an acid or base

3. Acids Acids have many distinctive properties:Acids have many distinctive properties: Acidic compounds give foods a sour or tart tasteAcidic compounds give foods a sour or tart taste Aqueous solutions of acids are electrolytesAqueous solutions of acids are electrolytes Acids cause chemical dyes, called acid-base indicators to change colorAcids cause chemical dyes, called acid-base indicators to change color

4. Bases are compounds that react with acids to form water and a salt Some characteristics of Aqueous solutions are a slippery feel and a bitter taste Bases can be strong or weak electrolytes and bases will change the color of acid-base indicators Antacids use a variety of bases to neutralize excess stomach acid

5. Acids - They form H+ ions in aqueous solutions HCl (water)  H+ & Cl- Bases- They yield OH- ions in aqueous solutions NaOH (water)  OH- & Na+ The oldest of the acid- base theories

6. Acids- -Hydrogen-ion donor -They are positive and to balance out, they can give H+ ions Bases- -Hydrogen-ion acceptor -OH- or another ion accepts the positive ions to neutralize The most common acid-base theory used today

7. Acids- -Accepts a pair of electrons to form a covalent bond -(They can accept negative electrons to help neutralize the atom)‏ Bases- -A substance that can donate a pair of electrons to form a covalent bond. -(This atom is negative already, therefore it can give off negative electrons to help balance the atom)‏ The acid-base theory used by organic chemists

8. Arrhenius Acids + Bases Acid + Base Salt + Water HCl + NaOH NaCl + HOH HCl + Ca(OH) 2

9. Bronsted-Lowry Acids + Bases acid + base → conjugate acid + conjugate base HCl + NaOH → H 2 O + NaCl In this case, water is the conjugate acid (potential H + i.e. proton donor). In this case, NaCl is the conjugate base (potential H + acceptor). HNO 3 + Ca(OH) 2 →

10. Binary Acids- -2 elements -the prefix is “hydro” ends in “ic” -HCl  Hydrochloric Acid -HBr  Hydrobromic Acid -HI -HF Ternary Acids- -3 elements or more -the higher number of oxygens of the polyatomic ion, it ends in “ic” Ex. sulfate -the lower number of oxygens ends in “ous” Ex. sulfite -no “hydro” prefix -name based on polyatomic ion -H 2 CO 3  carbonic -H 3 PO 4 -HNO 3 Bases- are named in the same way as all other ionic compounds

11. The acidity of a water sample is measured on a pH scale. This scale ranges from 0(Maximum acidity) to 14(Maximum alkalinity). The middle of the scale represents the neutral point. The acidity increases from neutral toward 0.

12. pH= -log[H+] When [H+]= 1x10 -7, the pH is 7  neutral Acidic Solution== pH<7.0 [H+] is greater than 1x10 -7 mol/L Basic Solution==pH>7.0 [H+] is less than 1x10 -7 mol/L All contents copyright of ISA © 1995-2006 All rights reserved. www.isa.org/Images/ InTech/Oct2002/20021048.gif

13. pH = -log [H + ] Therefore: pH 7 = -log 10 -7 M H + ions pH 6 = -log 10 -6 M H + ions pH 5 = -log 10 -5 M H + ions NOTE: A change from one pH unit to another is a tenfold change in concentration. pH 5 is ten times more acidic than pH 6 and one hundred times more acidic than pH 7. The mathematics of pH

14. pOH = -log [OH - ] Therefore: pOH 1 = -log 10 -1 M OH - ions pOH 2= -log 10 -2 M OH - ions pOH 3 = -log 10 -3 M OH - ions NOTE: A change from one pOH unit to another is a tenfold change in concentration. pOH 1 is ten times more basic than pOH 2 and one hundred times more basic than pOH 3. The mathematics of pOH

15. Reciprocal Relationships pH = -log [H + ] [H + ] = antilog -pH or 10 (-pH)‏ NOTE: On most calculators, antilog is the 2nd function log button. This same mathematical setup work for pOH too! pH + pOH = 14 pK a + pK b = 14

16. What about weak acids and bases? There are only six strong acids and six strong bases (see p. 376 in Masterson and Hurley)‏ All other acids and bases are considered weak, and DO NOT completely disssociate in water. In order to find the pH or pOH of a weak acid or base the equilibrium equation must be used. It is called the K a for acids and the K b for bases K a X K b = 1 X 10 -14

17. Using the Equilibrium Equation K a or K b = [products] [reactants] For purposes of use in this class you can change the equation as follows: K a or K b = x 2 original solution M Example: 0.1 M HF xM H 1+ + xM F 1- 6.9 x 10-4 = x 2 0.1 M The x can be used to find the pH since it is the dissociated hydrogen ion concentration [H 1+ ] of the weak acid, or the pH can be used as the value for x. Using this equation for polyatomic acids is more complex.

18. pH and Environmental Effects

20. SO x + H 2 O--> H 2 SO 4 --Sulfuric H 2 SO 3 --Sulfurous NO x + H 2 O--> HNO 3 --Nitric HNO 2 --Nitrous --The Sulfur found from emissions is naturally found in fossil fuels, in oil and coal. (gasoline)‏ --Burned to make: electricity --The Nitrogen and Oxygen are both found in air. They combine during high combustion processes.

21. Acid Rain Websites Basic Info Graphs and facts Soil type

22. Heartburn- -occurs in the Esophagus which has no mucus lining -Acid from the stomach backs into the Esophagus Ulcer- -Occurs in the stomach which has a thick mucus lining -The gastric juices have a pH of 1-2 -if there is a “hole” in the stomach acid hits nerve cells and forms an ulcer H.pylori bacterial infection

23. Digestive System Diagram June edition 2006 www.proctitispages.force9.co.uk/www.proctitispages.force9.co.uk/

24. Heartburn Heartburn is a pain behind the breast bone, often described as ‘burning’ in quality. Pain can also be felt at the same level in the mid-line of the back. Most people suffer from heartburn at one time or another. In fact heartburn has nothing to do with the heart - it is a digestive problem. Heartburn is generally related to meals and posture and can often be relieved by remedies for indigestion. Acid is present in the stomach to digest food. Heartburn occurs when small amounts of this acid rise up into the gullet ( esophagus ) - the tube which carries food from the mouth to the stomach. This is called reflux. The gullet, unlike the stomach, does not have a protective lining. So when it is exposed to the acid, it can become inflamed and painful. Acid is present in the stomach to digest food. Heartburn occurs when small amounts of this acid rise up into the gullet ( esophagus ) - the tube which carries food from the mouth to the stomach. This is called reflux. The gullet, unlike the stomach, does not have a protective lining. So when it is exposed to the acid, it can become inflamed and painful.

25. Ulcers What causes peptic ulcers? The contents of the stomach are acidic. The acid helps to protect the body from infection and helps break down the food that is eaten. The lining of the stomach and duodenum is covered in mucus (a thick, smooth fluid), which protects it from this acid. An ulcer can result when the stomach produces excess acid or there is insufficient mucus to protect the lining from damage. There are several factors that increase a person's risk of getting a peptic ulcer: infection with bacteria called Helicobacter pylori (H. pylori) - this is almost always present in people with ulcers, although it's also found in the stomachs of many people without ulcers or indigestion symptoms regularly taking certain medicines, particularly aspirin and other non- steroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen, naproxen and diclofenac smoking drinking alcohol in excess

26. http://www.lib.uiowa.edu/hardin/ md/pepticulcer.html -Normal mucosal folds ("rugae") in the gastric body. -Gastric Ulcer -Perforated ulcer Copyright © 1999-2004 by Fifth Dimension Technologies. All rights reserved www.5dt.com/products/ pgastroatlas.html

28. Acidosis Alkalosis pH less than 7.35 greater than 7.45 Breathing hypoventilation hyperventilation Blood Gases O 2 (down) CO 2 (up) O 2 (up) CO 2 (down)‏ Nervous SystemSlows-comaSpeeds up-- convulsions Treatment Oxygen, BiCarbonate IV Paper Bag HCO 3 1- (or mask)