Chapter 24: Solutions, Acids, and Bases

Section 4: Strength of Acids and Bases

Strong and Weak Acids and BasesStrength of Acids and BasesStrength of Acids and Bases

• The strength of an acid or base depends on how many acid or base particles dissociate into ions.

• When a STRONG ACID dissolves in water, almost 100 percent of the acid molecules dissociate into ions.

Strong and Weak Acids and Bases

Strength of Acids and BasesStrength of Acids and Bases

• When a WEAK ACID dissolves in water, only a small fraction of the acid molecules dissociates into ions.

When a Weak Acid dissolves in water almost 100 % of the acid molecules dissociate into ions.

A. TrueB. False

Strong and Weak Bases

Strength of Acids and BasesStrength of Acids and Bases

• A STRONG BASE dissociates completely in solution.

• A WEAK BASE is one that does not dissociate completely.

When a Strong Base dissolves in water almost 100 % of the base molecules dissociates into ions.

A. TrueB. False

Strength and Concentration

Strength of Acids and BasesStrength of Acids and Bases

• The terms STRONG AND WEAK refer to the ease with which an acid or base dissociates in solution.

• DILUTE AND CONCENTRATED are used to indicate the concentration of a solution, which is the amount of acid or base dissolved in the solution.

Dilute and concentrated relates to which terms?

A. Ease with which an acid or base dissociates in a solution.

B. Use to indicate the concentration of a solution.

Strong and Weak relates to which terms?

A. Ease with which an acid or base dissociates in a solution.

B. Use to indicate the concentration of a solution.

pH of a Solution

Strength of Acids and BasesStrength of Acids and Bases

• The pH of a solution is a measure of the concentration of H+ ions in it.

• The pH measures how acidic or basic a solution is.

pH is measure of ____ ions.A. H2O

B. H+

C. OH-

pH of a Solution

Strength of Acids and BasesStrength of Acids and Bases

• One way to determine pH is by using INDICATOR PAPER.

• The final color of the pH paper is matched with colors in a chart to find the pH.

• An instrument called a pH meter is another tool to determine the pH of a solution.

Blood pH

Strength of Acids and BasesStrength of Acids and Bases

• The pH of blood must remain between 7.0 and 7.8

• Some enzymes cannot work outside this pH range.

• BUFFERS are solutions containing ions that react with additional acids or bases to minimize their effects on pH

What is the difference between a strong acid and a weak acid?

A. Weak acids almost completely dissociate.

B. Strong acids almost completely dissociate.

C. By spelling only.

Question 1

What is the difference between the terms “strength” and “concentration?”

A. Strength refers to the ease with which an acid or base dissociates in solution. Concentration is the amount of an acid or base dissolved in the solution.

B. Concentration refers to the ease with which an acid or base dissociates in solution. Strength is the amount of an acid or base dissolved in the solution.

Question 2

The pH of a solution is a measure of the concentration of _________ in the solution.

A. H+

B. H3O+

C. COOHD. HCl

Question 3