General, Organic, and Biological Chemistry: Chapters 7, 8, and 9 Review

Vocabulary practice flashcards covering intermolecular forces, solutions, solubility, membrane transport, chemical equilibrium, acids and bases, and physiological buffer systems from Chapters 7, 8, and 9.

Vapor Pressure

The pressure exerted by gas molecules above a liquid in a closed container once a physical dynamic equilibrium between evaporation and condensation has been established.

Boiling Point

The temperature at which the vapor pressure of a liquid equals the external atmospheric pressure, providing molecules sufficient energy to overcome attractive forces and transition to the gas phase.

Changes of State

Physical phase transitions between solid, liquid, and gas states, which include melting and freezing, vaporization and condensation, and sublimation and deposition.

London Dispersion Forces

Momentary, weak attractive forces occurring between all molecules caused by temporary induced dipoles when electrons become unevenly distributed over a molecule's surface; the sole attractive force present in nonpolar molecules.

Dipole–Dipole Attraction

An intermolecular force occurring between polar molecules that possess permanent dipoles resulting from differences in electronegativity among their bonded atoms.

Hydrogen Bonding

A strong noncovalent attraction requiring the interaction between an electron-deficient hydrogen atom bonded to an electronegative atom (donor) and an unshared electron pair on another electronegative atom (acceptor).

Ion–Dipole Attraction

An electrostatic attractive force occurring between an ion carrying a full charge (such as $\text{Na}^+$ or $\text{Cl}^-$) and the partial charge of a polar molecule (such as water).

Salt Bridge (Ionic Attraction)

The electrostatic attraction between oppositely charged ions or charged functional groups (such as a carboxylate anion and a protonated amine cation); the strongest noncovalent attractive force in biological systems.

Golden Rule of Solubility

The principle stating that "like dissolves like," meaning molecules with similar polarity and compatible types of intermolecular attractive forces will dissolve in one another.

Hydration

The solvation process specific to aqueous solutions wherein multiple water molecules surround and stabilize individual solute ions or polar molecules through noncovalent attractive forces.

Amphipathic

Describing a compound containing both a distinct polar (hydrophilic) region and a nonpolar (hydrophobic) region, such as fatty acids, soaps, and phospholipids.

Micelle

A spherical aggregate of amphipathic molecules in water, arranged such that nonpolar hydrophobic tails associate internally via London forces while ionic hydrophilic heads form the external shell facing water.

Emulsifier

An amphipathic substance (such as soap or bile acid) that facilitates the suspension and stabilization of nonpolar and polar compounds within the same mixture.

Triglyceride

A hydrolyzable lipid composed of a glycerol backbone esterified to three fatty acid chains; classified as solid fats or liquid oils depending on the degree of hydrocarbon chain saturation.

Fat vs. Oil

Fats are animal-derived solid triglycerides with mainly saturated, straight-chain hydrocarbon tails that stack tightly; oils are plant-derived liquid triglycerides containing cis double bonds that kink the chains and impede packing.

Phospholipid

An amphipathic membrane lipid comprising a glycerol backbone esterified to two nonpolar fatty acid hydrocarbon tails and one ionic, polar phosphate-containing head group.

Fluid Mosaic Model

A model of membrane structure depicting a fluid double layer of phospholipids in which integral and peripheral proteins float like "icebergs" in a "sea" of lipids alongside cholesterol and carbohydrates.

Steroid Nucleus

A rigid fused four-ring carbon framework characteristic of steroids like cholesterol, estrogen, testosterone, and bile acids.

Solution

A transparent, homogeneous mixture composed of at least one solute evenly dispersed throughout a solvent, characterized by particles that do not settle upon standing and do not chemically react.

Colloid vs. Suspension

A colloid contains intermediate-sized particles that remain uniformly dispersed without settling; a suspension contains large particles that settle over time or separate upon centrifugation.

Henry's Law

A gas law stating that the solubility of a gas dissolved in a liquid is directly proportional to the partial pressure of that gas above the liquid.

Strong Electrolyte

A solute, such as a soluble ionic compound or strong acid, that dissociates completely ($100\%$) into ions in aqueous solution, thereby conducting electricity strongly.

Nonelectrolyte

A polar covalent substance (such as glucose or isopropanol) that dissolves in water as intact, uncharged molecules without ionizing, thus conducting no electric current.

Equivalent ($\text{Eq}$)

A unit relating the quantity of an ionic solute to the electrical charge it carries, defined as the moles of an ion multiplied by the absolute value of its ionic charge.

Molarity ($M$)

A quantitative concentration unit expressing the moles of solute contained per liter of total solution ($\text{moles solute} / \text{L solution}$).

Parts per Million ($\text{ppm}$)

A concentration unit for dilute solutions representing parts of solute per $10^6$ parts of solution, equivalent to $1\,\text{mg of solute per liter of solution}\,(1\,\text{mg/L})$.

Dilution Equation

The mathematical equation $C_{\text{initial}}V_{\text{initial}} = C_{\text{final}}V_{\text{final}}$, stating that the total moles or mass of solute remain constant when solvent is added to dilute a solution.

Osmosis

The net movement of water molecules across a semipermeable membrane from a region of lower solute concentration (more water) toward a region of higher solute concentration (less water).

Osmotic Pressure

The hydrostatic pressure exerted on a semipermeable membrane by water entering a solution during osmosis; increases with higher solute concentration.

Isotonic Solution

A solution whose solute concentration and osmotic pressure match that of the cytoplasm inside cells (e.g., $0.90\%\,(m/v)\,\text{NaCl}$ or $5\%\,(m/v)\,\text{D-glucose}$), producing zero net movement of water.

Hypotonic Solution

A solution possessing a lower solute concentration (higher water concentration) than the interior of a cell, driving water into the cell and causing swelling and potential rupture (lysis or hemolysis).

Hypertonic Solution

A solution possessing a higher solute concentration (lower water concentration) than the cellular interior, drawing water out of the cell and leading to shriveling (crenation).

Dialysis

A membrane transport process wherein small waste molecules and excess ions diffuse from blood (higher concentration) across a semipermeable membrane into a dialysate fluid or urine (lower concentration), while large molecules and cells are retained.

Membrane Transport Mechanisms

The three modes of crossing a phospholipid bilayer: passive diffusion (no energy, no protein, down gradient), facilitated transport (no energy, channel protein required, down gradient), and active transport (ATP energy required, channel protein required, against gradient).

Arrhenius Acid and Base

An Arrhenius acid dissociates in water to release hydrogen ions ($\text{H}^+$); an Arrhenius base is an ionic compound that dissociates in water to release hydroxide ions ($\text{OH}^-$) and metal cations.

Brønsted–Lowry Acid and Base

A Brønsted–Lowry acid is a substance that donates a proton ($\text{H}^+$); a Brønsted–Lowry base is a substance that accepts a proton ($\text{H}^+$).

Hydronium Ion ($\text{H}_3\text{O}^+$)

The positively charged species formed when a donated proton ($\text{H}^+$) binds to an unshared electron pair of a water molecule in aqueous solution.

Strong Acid

An acid that ionizes completely ($100\%$) in water to yield hydronium ions and conjugate base anions; the six recognized strong acids are $\text{HClO}_4$, $\text{H}_2\text{SO}_4$, $\text{HI}$, $\text{HBr}$, $\text{HCl}$, and $\text{HNO}_3$.

Weak Acid

An acid (such as acetic acid, $\text{CH}_3\text{COOH}$) that only partially ionizes in water (approximately $\sim 5\%$), establishing a dynamic equilibrium between unionized acid and products.

Neutralization Reaction

A chemical reaction between an acid and a base that produces water and an ionic salt, neutralizing the acidic and basic properties of both starting materials.

Chemical Equilibrium

A dynamic state in a reversible reaction where the rate of the forward reaction equals the rate of the reverse reaction, maintaining steady concentrations of all reactants and products.

Equilibrium Constant ($K$)

The ratio of the molar concentrations of products to reactants at equilibrium, each raised to the power of their balanced stoichiometric coefficients ($K = \frac{[\text{products}]}{[\text{reactants}]}$), excluding pure solids and liquids.

Le Châtelier's Principle

The rule stating that when an external stress (concentration, temperature, or pressure change) is imposed on a system at equilibrium, the system will shift its position in the direction that relieves the stress.

Acid Dissociation Constant ($K_a$)

The equilibrium constant expression governing the ionization of a weak acid in water ($K_a = \frac{[\text{H}_3\text{O}^+][\text{A}^-]}{[\text{HA}]}$); larger numerical values correspond to stronger weak acids.

$$pK_a$$

The negative logarithm of the acid dissociation constant ($pK_a = -\log K_a$); lower $pK_a$ values signify greater acid strength.

Autoionization of Water ($K_w$)

The reversible equilibrium in which two water molecules form hydronium and hydroxide ions, governed by $K_w = [\text{H}_3\text{O}^+][\text{OH}^-] = 1.0 \times 10^{-14}$ at $25\,^\circ\text{C}$.

pH Scale

A logarithmic measure of solution acidity defined as $pH = -\log[\text{H}_3\text{O}^+]$; values below 7 indicate acidity, equal to 7 indicate neutrality, and above 7 indicate basicity.

Conjugate Acid–Base Pair

Two chemical species related solely by the transfer, gain, or loss of a single proton ($\text{H}^+$), such as $\text{CH}_3\text{NH}_2$ and $\text{CH}_3\text{NH}_3^+$.

Henderson–Hasselbalch Equation

An equilibrium expression ($pH = pK_a + \log\frac{[\text{conjugate base}]}{[\text{acid}]}$) used to determine the ratio of ionized (water-soluble) to un-ionized (membrane-diffusible) drug forms in biological tissues.

Buffer

A solution composed of a weak acid and its conjugate base (or a weak base and its conjugate acid) that resists significant pH changes when small amounts of acid or base are added.

Bicarbonate Buffer System

The primary buffer maintaining human blood pH strictly between 7.35 and 7.45 via the multi-step equilibrium: $2\text{H}_2\text{O}(l) + \text{CO}_2(g) \rightleftharpoons \text{H}_2\text{CO}_3(aq) + \text{H}_2\text{O}(l) \rightleftharpoons \text{H}_3\text{O}^+(aq) + \text{HCO}_3^-(aq)$.

Homeostasis

The physiological capacity of an organism to regulate its internal chemical and physical environment (including blood pH, temperature, and fluid volume) within narrow, viable parameters.

Respiratory Acidosis

An acidic blood condition ($pH < 7.35$) caused by hypoventilation, leading to $\text{CO}_2$ accumulation that shifts the bicarbonate equilibrium right to generate excess $\text{H}_3\text{O}^+$.

Respiratory Alkalosis

A basic blood condition ($pH > 7.45$) caused by hyperventilation, which excessively clears $\text{CO}_2$ from the lungs and pulls $\text{H}_3\text{O}^+$ out of the blood to shift the equilibrium left.

Metabolic Acidosis and Alkalosis

Metabolic acidosis results from excess metabolic acid production (e.g., diabetic ketoacidosis) and is treated with IV bicarbonate; metabolic alkalosis results from loss of acid (e.g., severe vomiting) and can be treated with ammonium chloride.