(5) Module 5 (Acid-Base Equilibria) Lecture 2 (Part A-C)

Approximation only works when?

X is less than 5% of the initial concentration

(5% Rule or 5% Assumption)

The 5% rule can be used for both weak acids and weak bases (T/F)

True

What does the 5% Rule mean?

Less than 5% of the original acid dissociated

Most of it is still acid form, not ionized

If the 5% Rule fails, what do you use?

Quadratic

The larger the Kb value=

The more product forms (OH-)

(The stronger the weak base)

For the most part, we don’t consider Kb values for strong bases because?

They dissociate 100%

Picture

REMEMBER: The larger the Kb value

The stronger the weak base

What’s an important characteristic for the majority of weak bases?

The presence of the N atom

When some salts are dissolved in water, what can happen?

Some can either form an acidic or basic solution

If the cation is a conjugate acid of weak base, solution will be?

ACIDIC

If the anion is a conjugate base of a weak acid, solution will be?

BASIC

Some transition metal salts dissolved in water result in?

Acidic solutions