pH

Acids and Bases and pH : 

Acids and Bases and pH

Different Properties : 

Different Properties Acids Usually liquids or gases Many soluble in water Taste sour Produce H+ ion in water Bases Often solids Some soluble in water Taste bitter Solutions feel slippery Produce OH- ion in water

Acid and Base Definitions : 

Acid and Base Definitions Arrhenius Acids form hydrogen ions (H+) in solution Bases form hydroxide ions (OH-) in solution Brønsted-Lowry Acids donate a proton in a reaction Bases accept a proton in a reaction

Slide 4: 

H The hydrogen atom The hydrogen atom - 1p+ The hydrogen atom - 1p+ & 1e- Reacts by losing an electron Leaves an H+ behind The hydrogen ion - 1p+ +

Acid and Base Definitions : 

Acid and Base Definitions Ahrennius definition is limiting Brønsted-Lowry is broader All Ahrennius acids and bases are Brønsted-Lowry acids and bases Not All Brønsted-Lowry acids and bases are Ahrennius acids and bases`

Neutralization Reaction : 

Neutralization Reaction Acids and Bases react to neutralize each other. Equivalence point All of the acid has reacted with all of the base Moles of acid = moles of base

Self Ionization of Water : 

Self Ionization of Water Water is able to undergo an acid base reaction with itself. H2O (l) + H2O (l)  H3O+ (aq) + OH- (aq)

Self Ionization of water. : 

Self Ionization of water. This reaction heavily favors the reactants. Very little product is made. In neutral water the concentration of each is: [H3O+] = 1.0 x 10-7M [OH-] = 1.0 x 10-7M

Self Ionization of Water : 

Self Ionization of Water When the [H3O+] or [OH-] increases, the other decreases. [H3O+] x [OH-] = 1.0 x 10-14

Acid and Base Solutions : 

Acid and Base Solutions Acid [H3O+] > 1.0 x 10-7M Neutral [H3O+] =1.0 x 10-7M Base [H3O+] <1.0 x 10-7M

pH : 

pH pH is the value used to represent the acidity of a solution based on the logarithm of [H3O+] . pH = - log [H3O+] pH Scale 0-14,

The pH scale. : 

The pH scale. 0-7 acidic 7 neutral 7-14 basic

pH : 

pH To estimate pH, look at the exponent of the [H3O+] ion. Ex. [H3O+] = 1.0 x 10-7 pH = 7 [H3O+] = 1 x 10-3 pH = 3 [H3O+] = 1 x 10-11 pH = 11

pH More Examples : 

pH More Examples If the coefficient is not exactly 1, than the pH is an approximately what the exponent is. [H3O+] = 2.5 x 10-5 pH ~ 5 [H3O+] = 7.4 x 10-8 pH ~ 8 [H3O+] = 1.2 x 10-1 pH ~ 1

Differences in pH : 

Differences in pH A difference of 1 in pH corresponds to a difference of 10x in [H+] Example: [H+] = 1.0 x 10-2 M pH = 2 [H+] = 1.0 x 10-1 M pH = 1 1.0 x 10-1 M = 10.0 x 10-2 M pH 1 is 10 times as acidic as pH 2

Differences in pH : 

Differences in pH A difference of 2 in pH corresponds to a difference of 100x in [H+] Example: [H+] = 1.0 x 10-6 M pH = 6 [H+] = 1.0 x 10-4 M pH = 4 1.0 x 10-4 M = 100.0 x 10-6 M pH 4 is 100 times as acidic as pH 6

pOH : 

pOH pOH is done the same as pH, however you look at the [OH-] instead of [H3O+] pH + pOH = 14

pH and pOH : 

pH and pOH Since [H3O+] x [OH-] = 1.0 x 10-14, than, pH + pOH = 14 Ex. If the pH is 4, the pOH is 10.

Calculating [H3O+] from pH : 

Calculating [H3O+] from pH [H3O+] = 10-pH Ex. If the pH is 5, the [H3O+] = 1.0 x 10-5. If the pH is 12, the [H3O+] = 1.0 x 10-12.

pH differences : 

pH differences Find the [H3O+] of a solution with pH of 3 Find the [H3O+] of a solution with pH of 2

pH differences : 

pH differences Find the [H3O+] of a solution with pH of 3 [H3O+] = 1.0 x 10-3 Find the [H3O+] of a solution with pH of 2 [H3O+] = 1.0 x 10-2

Equations to Know : 

Equations to Know [H3O+] x [OH-] = 1.0 x 10-14 pH = - log [H3O+] pOH = - log [OH-] pH + pOH = 14 [H3O+] = 10-pH

Weak Acids and Bases : 

Weak Acids and Bases Weak acids do not completely ionize, therefore, the pH of an weak acid is always higher than the pH of a strong acid at equal concentrations, but less than 7. Weak bases do not completely ionize, therefore, the pH of a weak base is always lower than the pH of a strong acid at equal concentrations, greater than 14.