CHEM - ICE Tables + Acid-Base Equilibria

Initial

• Use given initial concentrations of reactants

• Always start with zero products

Change

Use stoichiometric coefficients to subtract mX from reactants or add nX to products

Equilibrium

• If given Keq: solve for X and equilibrium concentrations

• If given equilibrium concentration, determine concentrations for all and calculate Keq

When K<5%

assume x is small and ignore it in the denominator

How to check 5% rule?

(X/initial concentration) x 100

how to get rid of ln?

e^x

Bronsted-Lowry says that acids are proton donors and bases are proton…

acceptors

Conjugate acids and bases act as the…

acid or base in the reverse reaction

Ka =

products/reactants

If Ka >> 1 that means its a

strong acid

K is the equilibrium constant and it is __________ dependent

temperature

On the pH scale, the red side is lower pH and the middle (green) is neutral and the purple is higher pH. Where do acids and bases lie on the scale?

Acids on red side (smaller pH), base on purple side (larger pH)

Acidic

< 7

Basic

> 7

pOH scale is the opposite of pH scale

7 neutral

< 7 basic

> 7 acidic

pH + pOH =

14

Significant figures for pH and pOH =

#of decimal places

HA =

Acid

A =

Base

What is a polyprotic acid?

An acid that can donate multiple protons (H⁺)

A strong acid has a Ka _____ 1

much greater than

What’s the trend for Ka of polyprotic acids?

As protons are removed, the Ka decreases and the acids become weaker

The stronger the acid, the _________ the conjugate bases

weaker

Kw =

Ka x Kb

Ka and Kb are ______ proportional

inversely

Lower ionization =

weaker acid

Higher Ka =

stronger

K₂CO₃

Basic

CaCl₂

neutral

KCN

Basic

NaCl

neutral

KNO₃

neutral

NH₄Cl

acidic

Na₂CO₃

Basic

Monoprotic

1 proton to give up (H⁺)

Diprotic

2 protons to give up

Triprotic

3 H⁺

Each proton given up =

weaker

Strong acid + strong base =

neutral salt

Strong acid + weak base =

acidic salt

Weak acid + strong base

basic salt

→ Or ←

completely ionized

<->

not completely ionized

Strong acids and bases react with water =

completely ionized

Weak acids and bases react =

only partially ionize

Larger Ka = more acidic and

lower pH

Larger Ka =

more product and stronger acid

Smaller Ka =

more reactants and a weaker acid

A buffer is a solution that has the ability to…

resist changes in pH when limited amounts of acids or bases are added to it

Buffers are made by combining

a weak acid or base with its conjugate

Strong acid = readily lose a

proton

A strong acid has a stable but weak conjugate base

not dying to pick up a proton

Weak acid is not very willing to _____ a proton

lose

increase [H₃O⁺]

increase acidity

decrease pKa

increase acidity

[H₃O⁺] > 10^-7

acidic solution

[H₃O⁺] < 10^-7

basic solution

[H₃O⁺] = 10^-7

neutral solution

Strong acids deprotonate

completely

weak acids deprotonate

partially

pH = pKa when buffer has equal amounts of

HA and A^-

more base than acid =

higher pH than pKa

more acid than base =

higher pKa than pH