2 Properties ACIDS BASES electrolyte electrolyte sour taste bitter taste sticky feelslippery feelturn litmus redturn litmus bluereact with acids to form water and a salt (ionic compound)react with bases to form water and a salt (ionic compound)
3 ExamplesACIDS: Most citrus fruits, tea, battery acid, vinegar, milk, soda, apples.BASES: Common household bases include baking soda, lye, ammonia, soap, and antacids..3
4 IndicatorsIndicators are substances that change color in the presence of an acid or a baseIndicators are made up of weak acids or weak basesExamples of indicators include pH paper, red and blue litmus paper, and phenolphthalein
5 Acids Affect Indicators: Blue litmus paper turns red in contact with an acid. It remains blue when in contact with a base or neutral solution.5
6 Bases affect indicators: Red litmus paper turns blue in contact with a base. It remains red when in contact with an acid or neutral solution.Phenolphthalein turns pink in a base. It is colorless in an acid or neutral solution.6
7 Definitions There are 3 definitions used to describe acids and bases: ArrheniusBrØnsted-LowryLewisThe most traditional is Arrhenius acids and bases.
10 Another common way to refer to hydrogen ions is to call them “protons” DefinitionsAnother common way to refer to hydrogen ions is to call them “protons”Brønsted-LowryAcids are proton (H+) donors.Bases are proton (H+) acceptors.HCl + H2O Cl– + H3O+acidconjugate basebaseconjugate acidConjugate acid – particle formed when a base gains a H+Conjugate base – particle that remains when an acid has donated a H+.
11 Definitions Lewis Lewis base Lewis acid Acids are electron pair acceptors.Bases are electron pair donors.Lewis baseLewis acid
12 White Board QuestionsWhen you wafted a substance your nose burned. Would this substance be an acid or a base?A hydrogen ion (H+) can also be called a _________ or ____________.Arrhenius acids are compounds that break up in water to give off _____________.What color litmus paper would you use to test an acid? What color will it turn?5. If your food tastes bitter, which do you think it could possibly be an acid or a base?ACIDProtonH3O+H+Blue turns redBASE12
13 White Board Questions6. A BrØnsted-Lowry base _________ hydrogen ions. 7. Phenolphthalein turns pink when it comes in contact with a(n) _________. 8. Which of the scientists defined the typical acid? 9. If you are eating and it has a sour taste, would that be an acid or a base? 10. If a piece of red litmus paper turns blue than it is a(n) ___________.acceptsbaseArrheniusacidbase13
14 Naming Acids Binary acids Contains 2 different elements: H and another Always has “hydro-” prefixRoot of other element’s nameEnding “-ic”
15 Examples of Binary Acids HI is hydroiodic acidH2S is hydrosulfuric acidHBr is hydrobromic acidHCl is hydrochloric acid
16 Naming Acids Ternary Acids - Oxyacids Contains 3 different elements: H, O, and anotherNo prefixName of polyatomic ion (p. 147)Ending “–ic” for polyatomic ion ending in “-ate” and “–ous” for ion ending in “-ite”
17 Examples of Ternary Acids ClO3 is chlorate so HClO3 is chloric acidPO4 is phosphateso H3PO4 is phosphoric acidPO3 is phosphiteso H3PO3 is phosphorous acidNO2 is nitrite HNO2 is nitrous acidNO3 is nitrate HNO3 is nitric acid
18 Naming Acids cont.HC2H3O2 or CH3COOHName is acetic acidCommon name = vinegar
20 Ion Product of Water H2O H+ + OH- Self- ionization of water – the simple dissociation of waterH2O H OH-Concentration of ea. ion in pure water:[H+] = 1.0 x 10-7M [OH-] = 1.0 x 10-7MIon-product constant for water (Kw), Where Kw = 1.0 x 10-14Kw = [H+] [OH-]Acid [H+] > [OH-]Base [H+] < [OH-]Neutral [H+] = [OH-]20
21 Calculating [H+] and [OH-] reverse the pH equationThe pH of a solution is 8. Find the [H+] and [OH-] and determine whether it is acidic, basic, or neutral.basic[H+] = 1 x 10-pH and [OH-] = 1 x 10-pOH[H+] = 1 x 10-8 M[OH-] = 1 x 10-(14-8) M = 1 x 10-6 M
22 Examples1. If the [H+] in a solution is 1.0 x 10-5M, is the solution acidic, basic or neutral?1.0 x 10-5 MWhat is the concentration of the [OH-]?Use the ion-product constant for water (Kw):Kw = [H+] [OH-]1.0 x = [1.0 x 10-5] [OH-]1.0 x = [OH-]1.0 x 10-51.0 x 10-(14-5)pH 5 = acidic1.0 x 10-9 M22
23 Examples2. If the pH is 9, what is the concentration of the hydroxide ion?Kw = [H+] [OH-]1.0 x M = [1.0 x 10-9M] [OH-]1.0 x 10-5 M = [OH-]14 = pH + pOH14 = 9 + pOH5 = pOH3. If the pOH is 4, what is the concentration of the hydrogen ion?Kw = [H+] [OH-]1.0 x M = [H+] [1.0 x 10-4 M]1.0 x M = [H+]14 = pH + pOH14 = pH + 410 = pH23
24 Examples Acidic since pH is 4 4. A solution has a pH of 4. Calculate the pOH, [H+] and [OH-]. Is it acidic, basic, or neutral?14= pH + pOH14= 4 + pOH10= pOHAcidic since pH is 4
25 Practice Problems: Classify each solution as acidic, basic or neutral. 1. [H+] = 1.0 x M2. [H+] = 0.001M3. [OH-] = 1.0 x 10-7 M4. [OH-] = 1.0 x 10-4 MBasic pH 101.0 x 10-3 acid pH 3Neutral14=pH+4 base pH 1025
26 [OH-] pOH pH [H+] 1 x 10-14 14 1 x 100 1 x 10-13 13 1 1 x 10-1 1 x 1001 x 10-131311 x 10-11 x 10-121221 x 10-21 x 10-111131 x 10-31 x 10-1010Increasing acidity41 x 10-41 x 10-9951 x 10-51 x 10-8861 x 10-61 x 10-77NeutralIncreasing basicity2626
27 White Board Practice Fill in the chart. [OH-]pOHpH[H+]81x 10-12101 x 10-31.0 X 10 -861.0 X 10 -62121.0 X 10 -21.0 X 10 -441.0 X1131.0 X
28 Fill in the chart. [OH-] pOH pH [H+] 8 1x 10-12 10 1 x 10-3 5 1 × 10-1 61.0 X 10 -62121.0 X 10 -21.0 X 10 -441.0 X1131.0 X91.0 X 10 -51.0 X 10 -91311.0 X
29 Strength or Concentration -+Strong Acid/BaseIonize completely in waterstrong electrolyteAcidsHClHNO3H2SO4HBrHIHClO4BasesNaOHKOHCa(OH)2Ba(OH)2
30 Strength or Concentration Weak Acid/Baseionize partially in waterweak electrolyte-+AcidsHFCH3COOHH3PO4H2CO3HCNBaseNH3
31 Strength or Concentration How strong or weak an acid or base is, depends on its degree of ionization.-+-+
32 pouvoir hydrogène (Fr.) pH Scale147INCREASINGACIDITYINCREASINGBASICITYNEUTRALpH is the negative logarithm of the hydrogen ion concentrationpH = -log[H+]pouvoir hydrogène (Fr.)“hydrogen power”
36 Neutralization Chemical reaction between an acid and a base. Products are a salt (ionic compound) and water.
37 ACID + BASE SALT + WATER NeutralizationACID + BASE SALT + WATERHCl + NaOH NaCl + H2OstrongstrongneutralHC2H3O2 + NaOH NaC2H3O2 + H2OweakstrongbasicSalts can be neutral, acidic, or basic.Neutralization does not mean pH = 7.
38 Titrationstandard solutionunknown solutionTitrationAnalytical method in which a standard solution is used to determine the concentration of an unknown solution.
39 Titration cont. Equivalence point (endpoint) Point at which equal amounts of H+ and OH- have been added.Determined by…indicator color changedramatic change in pH
40 moles H+ = moles OH- MV n = MV n Titration formula M: Molarity V: volumen: # of H+ ions in the acid or OH- ions in the base
41 Titration example42.5 mL of 1.3M KOH are required to neutralize 50.0 mL of H2SO4. Find the molarity of H2SO4.H2SO4M = ?V = 50.0 mLn = 2KOHM = 1.3MV = 42.5 mLn = 1MVn = MVnM(50.0mL)(2)=(1.3M)(42.5mL)(1)M= 55.25100M = 0.55M H2SO4
42 Review of Acid and Base Definitions ArrheniusMost specific/exclusive definitionCreated by Svante Arrhenius, SwedishAcid: compound that creates H+ in an aqueous solutionHNO3 H+ + NO3-Base: compound that creates OH- in an aqueous solutionNaOH Na+ + OH-
43 Review of Acid and Base Definitions Bronsted-LowryMore general definition than Arrhenius definitionMost commonly used definitionCreated by 2 scientists around the same time (1923)Acid: Molecule or ion that is a proton (H+) donorHCl + H2O H3O+ + Cl-Base: Molecule or ion that is a proton (H+) acceptorNH3 + H2O NH4+ + OH-
44 Review of Acid and Base Definitions LewisMost general definitionDefined by electrons and bonding rather than H+Created by the same scientist who electron-dot diagrams are named afterAcid: atom, ion, or molecule that accepts an electron pair to form a covalent bondNH3 + Ag+ [Ag(NH3)2]+Base: atom, ion, or molecule that donates an electron pair to form a covalent bondBF3 + F- BF4-