pH-used to measure how acidic or basic a substance is.

Determining pH:1)pH Meter-device used to determine pH of a solution

using a voltmeter +2 electrodes. .:VpH

2)Indicators-dyes used to determine pH of a substance. Turns different colors at various pH’s

Ex/phenolphthalein clearpink pH>7.6 litmus redblue pH>7 universal redpurple pH 1-14

Acids & Bases

Some natural dyes such as Cabbage Juice can be used as pH indicators. How would you calibrate these colors so if you used Cabbage Juice as an indicator, you would know the pH?

Even in ancient civilizations such as Teotihuacan in 1-200 A.D., Mesoamericans used natural pigments from the local cactus plant to produce 2 different colored dyes to paint the Pyramid of the Sun, Pyramid of the Moon, and other structures at the site.

See: http://studentweb.tulane.edu/~dhixson/teo/teo.htmlhttp://archaeology.la.asu.edu/teo/http://www.teotihuacan.com/

Arrhenius DefinitionAcids-contain H that ionizes into H+ in water

ex/ H2SO4 + 2H2O 2H3O+ + SO4-2

ex/ HI

monoprotic-HCl, HNO3, HBr, HI, HC2H3O2

diprotic-H2CO3, H2SO4

triprotic-H3PO4

H must be connected to a electronegative atom

Bases-contain OH that dissociates into OH- in water

ex/ NaOH Na+ + OH-

ex/ Mg(OH)2

HydroniumH+ + H2O H3O+

H2O

H2O = HOH.:water is both an acid & base

Bronsted-Lowry DefinitionAcid-H+ donor (loses H+)Base-H+ acceptor (gains H+)

ex/ NH3 + H2O NH4+ + OH-

ex/ H2CO3 + OH- HCO3- + H2O

base acid conjugate baseconjugate acid

Strong Acids & Bases-Fully separate(ionize) into ions in water .:Good conductors electricity in water!

Ex/ HCl + H2O H3O+ + Cl-

NaOH Na+ + OH-

Weak Acids & Bases-Not fully separate(dissociate) into ions in water .:poor conductors electricity in water!

Ex/ HC2H3O2 + H2O H3O+ + C2H3O2-

NH4OH NH4+ + OH-

ex/ Normal CO2 + H2O H2CO3 pH=5-6

Abnormal NO2 + H2O HNO3 pH=3-4

Abnormal SO2 + H2O H2SO4 pH=3-4Acid Rain

Strong Acid or Base Weak Acid or Base

Neutralization-Reaction involving an Acid & Base reacting together to produce a Salt & H2O pH=7

Ex/ upset stomach? HCl + Mg(OH)2 MgCl2 + H2O HCl + Ca(OH)2 CaCl2 + H2O

No Acid/Base Properties Ph=7

Buffers-Compounds used to keep pH set at a value. Weak acid + its salt

Ex/ lakes, pools, spas, blood H2CO3 + Na2CO3 pH=7.6

Uses of Acids & Bases

Titrations-Scientists use to determine concentration of unknown acidic/basic solution. Use Buret

-Uses: neutralization reaction balanced equation standardized solution unknown solution pH=7 equivalence point

Macid vacid = Mbase vbase pH=7

Ex/ Concentrated stomach acid?HCl + NaOH NaCl + H2O32mL 25.3mL ? 1.0mol/L

If 1:1 in balanced equation