AP chem acid base

Autoionization of water Kw

H3O and OH are equal

Knowing concentration of one of them allows you to find C of other

Some Cations (+) acidify solutions

Ionic compounds containing NH4 acidify solutions because it produces H3O and NH3 which isn’t strong enough to stop it from turning acidic.

When adding a positive ion it can attract the OH and shift equilibrium to make more OH and H and make the solution more acidic. Elements with small radius and more electronegative are more effective at this.

Some anions (-) make solutions basic

Anions that are conjugate bases of weak acids accept H from water to produce OH.

Salts with weak AB

Salts may contain both an acidic cation and basic anion.

Little to no effect on pH

Solubility and acids

The solubility of low soluble compounds increase as H increases

Common ion effect

Adding a compound with a common ion shifts equilibrium towards the original compounds.

Buffers

Resist pH change

AB and its salt

Titration indicators

HIn = H + in

Acidic shift left

Basic shift right

Change color when Hln ~ in

Choose indicator that pKa (indicator) ~ e point

Strong bases

Group 1 and Sr, Ca, Ba and OH

Weak bases contain N

Any lone pair on nitrogen can accept a H

Binary acid strength

More electronegative and larger radius makes for a stronger acid because the H use more loose.

Stronger acids have more stable CB

Inductive effect

Highly eneg elements attracts electrons away from bonds lower e density weakening the bond

Carboxylic and oxyids follow this as well

Titration words

Indicator changes color

Epoint - number of moles of titrant and analysts are equal

3 types of titration

Strong acid - strong base titration

Titration of a weak acid (analyte) by a strong base (titrant)

Titration of a weak base by a strong acid

SASB titration

Initial is close to 1 or 14

Epoint is 7

WASB titration

Initial is greater than 1

Half epoint is pKa

Initial to epoint is buffer zone

SASB RXN

Complete dissociation

H and OH form water

Kw = 1×10^-14

WASB WBSA RXN

Produces water and CB or CA of molecule

WAWB RXN

Don’t go into completion

Mostly undissociated

Proton transfer rxn

Ka/Kb

Larger Ka value means stronger acid

pKa/pKb

The stronger it is the smaller its value

Added together = 14 at 25C

Polyphonic acids

Have multiple Ka values

Always use first Ka value

First one always drives rxn to the left

Kw and different temps

Rxn is endothermic

Kw increases as temp increases and vv

Acidic above 25 and vv