Chem 111 Exam 3: Acid Base Equilibrium (from prof notes)

This collection of flashcards covers key vocabulary and concepts related to acid-base equilibrium in General Chemistry II.

Acid

A substance that donates a proton (H+) to another substance.

Base

A substance that accepts a proton (H+) from another substance.

Arrhenius Acid

A substance that produces H+ ions when dissolved in water.

Arrhenius Base

A substance that produces OH– ions when dissolved in water.

Brønsted-Lowry Acid

A substance that donates a proton in an acid-base reaction.

Brønsted-Lowry Base

A substance that accepts a proton in an acid-base reaction.

Conjugate Acid

The species formed when a base accepts a proton.

Conjugate Base

The species formed when an acid donates a proton.

Autoionization of Water

The process in which water acts as both an acid and a base, resulting in the formation of hydronium and hydroxide ions.

pH Scale

A logarithmic scale used to specify the acidity or basicity of an aqueous solution.

Strong Acid

An acid that completely dissociates in solution, leaving no undissociated molecules.

Weak Acid

An acid that only partially dissociates in solution, existing as a mixture of the acid and its conjugate base.

Ion Product Constant of Water (Kw)

The equilibrium constant for the autoionization of water, equal to [H3O+][OH−] at a given temperature.

Percent Ionization

The ratio of the concentration of ionized acid to the initial concentration of acid, expressed as a percentage.

Lewis Acid

An electron-pair acceptor in a chemical reaction.

Lewis Base

An electron-pair donor in a chemical reaction.

Oxyacids

Acids in which OH groups and possibly additional O atoms are bound to a central atom.

Amphiprotic Substance

A substance that can act as both an acid and a base, depending on the context.

Hydronium Ion (H3O+)

A water molecule that has accepted a proton; it represents an increase in acidity in aqueous solutions.

What is pH?

pH is a measure of the acidity or basicity of a solution, on a scale from 0 to 14.

What is pOH?

pOH is a measure of the concentration of hydroxide ions in a solution, also on a scale from 0 to 14.

What is the relationship between pH and pOH?

The sum of pH and pOH in a solution at 25°C equals 14: pH + pOH = 14.

What does a low pH indicate?

A low pH value indicates high acidity in a solution.

What does a high pH indicate?

A high pH value indicates high basicity (alkaline) in a solution.

What are some examples of strong acids?

Common strong acids include hydrochloric acid (HCl), sulfuric acid (H2SO4), and nitric acid (HNO3).

What are some examples of weak acids?

Common weak acids include acetic acid (CH3COOH), citric acid (C6H8O7), and carbonic acid (H2CO3).

What are some examples of strong bases?

Common strong bases include sodium hydroxide (NaOH), potassium hydroxide (KOH), and calcium hydroxide (Ca(OH)2).

What are some examples of weak bases?

Common weak bases include ammonia (NH3), sodium bicarbonate (NaHCO3), and pyridine (C5H5N).

How does the strength of an acid relate to its pKa value?

The strength of an acid is inversely related to its pKa; a lower pKa indicates a stronger acid.

How does the strength of a base relate to its pKb value?

The strength of a base is inversely related to its pKb; a lower pKb indicates a stronger base.

What is the role of acids and bases in buffer solutions?

Acids and bases in buffer solutions help maintain a stable pH by neutralizing small amounts of added acids or bases.

What is a neutralization reaction?

A neutralization reaction occurs when an acid reacts with a base to produce water and a salt.

What is ionization in the context of acids and bases?

Ionization refers to the process by which an acid or base dissolves in water and separates into its component ions.

What is a strong acid-strong base titration?

the equivalence point occurs at pH 7 with a sharp transition in the graph

What is a weak acid-strong base titration?

The equivalence point occurs at a pH greater than 7 because it forms a conjugate base and becomes basic

What is a strong acid-weak base titration?

the equivalence point occurs at a pH less than 7 because it forms a conjugate acid and becomes acidic