Acid-Base Equilibria & Solubility Practice Flashcards

A comprehensive set of vocabulary flashcards covering acid-base theories, pH calculations, buffer systems, titration mechanics, and solubility equilibrium based on the lecture transcript.

Arrhenius Acid

A substance that produces $H^+$ ions in water.

Arrhenius Base

A substance that produces $OH^-$ ions in water.

Brønsted-Lowry Acid

A substance that acts as a Proton ($H^+$) Donor.

Brønsted-Lowry Base

A substance that acts as a Proton ($H^+$) Acceptor.

Lewis Acid

A substance that acts as an Electron Pair Acceptor.

Lewis Base

A substance that acts as an Electron Pair Donor.

Conjugate Base

The species created when an acid loses its proton (e.g., $HCl \rightarrow Cl^-$).

Conjugate Acid

The species created when a base gains its proton (e.g., $H_2O \rightarrow H_3O^+$).

Amphoteric (Amphiprotic)

A substance that can act as either an acid or a base depending on what it reacts with, such as water.

Autoionization of Water

The process where water molecules collide to react with themselves to produce ions: $H_2O(l) + H_2O(l) \rightleftharpoons H_3O^+(aq) + OH^-(aq)$.

Kw (Ion Product Constant for Water)

The equilibrium constant for the autoionization of water, defined as $Kw = [H^+][OH^-] = 1.0 \times 10^{-14}$ (at $25^{\circ}C$).

Strong Acids

Acids that ionize $100\%$ in water, including $HCl$, $HNO_3$, $H_2SO_4$, $HI$, $HBr$, and $HClO_4$.

Strong Bases

Bases that dissociate $100\%$ into metal cations and $OH^-$ ions, specifically Group 1 and Group 2 hydroxides like $NaOH$, $KOH$, and $Ba(OH)_2$.

Weak Acids

Acids that ionize only partially ($< 5\%$) and stay mostly as molecules, such as $CH_3COOH$, $HF$, and $HCN$.

Monoprotic Acid

An acid that yields exactly one $H^+$ ion per molecule, such as $HCl$.

Polyprotic Acid

An acid that can yield more than one $H^+$ ion per molecule in a stepwise manner, such as $H_2SO_4$.

Acid Dissociation Constant ($Ka$)

The equilibrium constant for the ionization of a weak acid, where larger values indicate a stronger weak acid: $Ka = \frac{[H^+][A^-]}{[HA]}$.

Buffer Solution

A system made from a weak acid/base and its conjugate salt that resists significant changes in pH when small amounts of acid or alkali are added.

Buffer Plateau Region

A region on a weak-strong titration curve where the pH flattens out because the partially neutralized solution creates a functioning buffer system.

Half-Equivalence Point

The coordinate halfway to the equivalence point volume where $[HA] = [A^-]$ and $pH = pKa$.

Endpoint

The precise moment in a titration where $[HIn] = [In^-]$, causing the indicator to transition through a middle blend of colors.

Phenolphthalein

A chemical indicator with a transition range of $pH\,8.3 - 10.0$ that turns from colorless to pink.

Methyl Orange

A chemical indicator with a transition range of $pH\,3.1 - 4.4$ that turns from red to yellow.

Solubility Product Constant ($Ksp$)

A constant tracking the dynamic equilibrium in saturated solutions of ionic compounds; for $AgCl$, $Ksp = [Ag^+][Cl^-]$.

Molar Solubility ($x$)

The concentration of a salt that can dissolve per liter ($dm^3$) of water before reaching saturation.

Reaction Quotient ($Q$)

A value compared to $Ksp$ to predict precipitation; if $Q > Ksp$, a precipitate forms immediately.

Common Ion Effect

The phenomenon where the solubility of an ionic salt decreases when dissolved in water that already contains one of its component ions.