SCH4U Unit 4 Acid-Base Equilibrium Vocabulary

This set of vocabulary flashcards covers chemical equations, constants (Ka and Kb), and reaction favorability principles for weak acids and bases based on the SCH4U Unit 4 Equilibrium worksheets.

Weak Acid Dissociation General Form

The chemical equilibrium represented by the equation $HA + H_2O(l) \rightleftharpoons H_3O^+ + A^-$.

Weak Base Dissociation General Form

The chemical equilibrium represented by the equation $B(aq) + H_2O(l) \rightleftharpoons HB^+ + OH^-$.

Percent Dissociation

A percentage representing the extent to which an acid or base ionizes in a solution, often calculated using pH/pOH and initial concentration.

$$K_a$$

The acid dissociation constant that quantifies the strength of an acid in solution.

$$K_b$$

The base dissociation constant that quantifies the strength of a base in solution.

Conjugate Acid

The species formed (such as $HB^+$ or $H_3O^+$) when a base accepts a proton ($H^+$).

Conjugate Base

The species formed (such as $A^-$ or $OH^-$) when an acid donates a proton ($H^+$).

Boric Acid ($H_3BO_3$)

A weak acid with a provided $K_a$ value of $5.8 \times 10^{-10}$.

$$NO_2^-$$

A basic ion with a provided $K_b$ value of $1.96 \times 10^{-11}$.

$$HCO_3^-$$

A basic ion with a provided $K_b$ value of $2.27 \times 10^{-8}$.

$NH_3$ (Ammonia)

A weak base with a provided $K_b$ value of $1.75 \times 10^{-5}$.

Forward Reaction Favorability

Occurs in an acid-base reaction when the reactant acid is stronger than the conjugate acid produced (e.g., $H_3PO_4$ compared to $HF$).

Reverse Reaction Favorability

Occurs in an acid-base reaction when the conjugate acid produced is stronger than the reactant acid (e.g., $H_2Se$ compared to $Al(H_2O)_6^{3+}$).

$$Al(H_2O)_6^{3+}$$

The hexaaquaaluminum(III) ion which acts as an acid in aqueous solutions.

$$C_2H_3O_2^-$$

The acetate ion, a weak base with a provided $K_b$ value of $5.6 \times 10^{-10}$.