AP Chemistry Comprehensive Study Guide: Intermolecular Forces, Physical States, Gas Dynamics, Solutions & Spectroscopy

A set of 50 comprehensive vocabulary flashcards covering intermolecular forces, solid types, gas behavior and real gas deviations, solution dynamics, alloys, and spectroscopy concepts from the AP Chemistry review guide.

Intramolecular Forces

Covalent, ionic, or metallic bonds holding constituent atoms or ions together inside a molecule or formula unit, requiring chemical bond cleavage to overcome.

Intermolecular Forces (IMFs)

Non-covalent electrostatic attractions between separate, adjacent molecules or atoms that are overcome during physical phase changes while leaving chemical bonds intact.

Ion-Dipole Forces

Electrostatic attractions operating between a charged ion and the permanent dipole of a polar solvent molecule.

Hydration Shell

A structured arrangement of polar water molecules around a dissolved ion, where partially negative oxygen atoms ($\delta^-$) face cations and partially positive hydrogen atoms ($\delta^+$) face anions.

Coulomb's Law

Mathematical law governing electrostatic force: $F = k\frac{Q_1Q_2}{d^2}$, stating force strengthens with increasing charge magnitudes ($Q_1, Q_2$) and decreasing distance separating charge centers ($d$).

Hydrogen Bond

An unusually strong, specialized dipole-dipole attraction requiring a hydrogen atom covalently bonded to F, O, or N and an unshared lone pair on an adjacent small, electronegative F, O, or N atom.

Dipole-Dipole Attractions

Intermolecular forces operating between neutral molecules possessing permanent dipoles, governed by dipole magnitude and spatial alignment.

Dipole-Induced Dipole Forces

Weak attractive forces between a permanent dipole in a polar species and an electron cloud distortion induced in a neighboring non-polar species.

London Dispersion Forces (LDF)

Intermolecular attractions present in all chemical species and the sole attractive force in non-polar species, arising from temporary electron cloud distortions.

Polarizability

The ease with which an electron cloud distorts to form a temporary dipole; larger, more diffuse electron clouds exhibit higher polarizability and stronger dispersion forces.

Contact Surface Area

A structural factor where elongated, straight-chain isomers make extended surface contact to maximize cumulative London dispersion forces compared to compact, spherical isomers.

Ionic Solids

Solids composed of cations and anions bound in a lattice by Coulombic ionic bonds, characterized by high melting points, brittleness, and electrical conductivity only when molten or aqueous.

Molecular Solids

Solids composed of neutral molecules held together by intermolecular forces (LDF, dipole-dipole, H-bonds) with low to moderate melting points and non-conductivity.

Covalent Network Solids

Solids composed of atoms held in extended 2D or 3D lattices by covalent bonds ($sp^2$ or $sp^3$), featuring exceptionally high melting points and hardness.

Metallic Solids

Solids formed by metal cations surrounded by a mobile, non-directional sea of delocalized valence electrons, exhibiting malleability, ductility, and high electrical conductivity.

Ionic Brittleness

The shattering behavior of ionic crystals when mechanical force shifts lattice layers, aligning ions of like charge adjacent to each other and producing intense repulsive cleavage.

Metallic Malleability

The capacity of metals to deform under mechanical force because mobile delocalized electrons continuously adjust and shield shifted cations, preventing repulsive cleavage.

Diamond

An $sp^3$ hybridized carbon allotrope forming four single $\sigma$-bonds in a rigid 3D tetrahedral network, acting as an electrical insulator due to localized valence electrons.

Graphite

An $sp^2$ hybridized carbon allotrope composed of 2D hexagonal sheets with delocalized $\pi$-electrons that conduct electricity along the planes.

Crystalline Solids

Solids featuring ordered, repeating 3D unit cells with sharp, well-defined melting points.

Amorphous Solids

Solids featuring disordered molecular arrangements that lack long-range repeating periodicity, resulting in gradual softening rather than a sharp melting point.

Molar Heat of Vaporization ($\Delta H_{vap}$)

The energy required to completely overcome and sever all intermolecular attractions holding liquid particles together to yield isolated gas particles.

Molar Heat of Fusion ($\Delta H_{fus}$)

The energy required to partially disrupt and expand lattice order during the phase change from solid to liquid, which is smaller in magnitude than $\Delta H_{vap}$.

Boyle's Law

An empirical gas law stating that gas volume is inversely proportional to pressure ($V \propto 1/P$) at constant temperature and mole amount.

Charles's Law

An empirical gas law stating that gas volume is directly proportional to absolute Kelvin temperature ($V \propto T$) at constant pressure and mole amount.

Avogadro's Principle

A gas principle stating that gas volume is directly proportional to the number of moles ($V \propto n$) at constant temperature and pressure.

Ideal Gas Law

Unified equation of state modeling gas behavior: $PV = nRT$, where $R = 0.0821\,\frac{L\cdot atm}{mol\cdot K}$ and temperature $T$ is in Kelvin.

Gas Density ($\rho$)

Gas property derived from the ideal gas law: $\rho = \frac{P\cdot MM}{R\cdot T}$, expressing mass per volume in units of $\text{g/L}$.

Gas Molar Mass ($MM$)

The mass per mole of a gas, calculated from algebraic rearrangement of the ideal gas law: $MM = \frac{\text{mass}\cdot R\cdot T}{P\cdot V} = \frac{\rho\cdot R\cdot T}{P}$.

Dalton's Law of Partial Pressures

Law stating that the total pressure of a non-reacting gas mixture equals the sum of individual component partial pressures: $P_{total} = \sum P_i$.

Mole Fraction ($X_A$)

A dimensionless concentration metric defined as $X_A = \frac{n_A}{n_{total}}$, used to calculate component partial pressure via $P_A = X_A P_{total}$.

Wet Gas Correction

The stoichiometric correction applied when collecting gas over water by displacement: $P_{dry\,gas} = P_{atm} - P_{H_2O}$.

KMT Negligible Particle Volume Postulate

Kinetic Molecular Theory postulate assuming the physical volume occupied by individual gas particles is negligible relative to total container volume.

KMT Elastic Collisions Postulate

Kinetic Molecular Theory postulate stating collisions between gas particles and container walls conserve total system kinetic energy without net loss.

KMT Temperature Proportionality Postulate

Kinetic Molecular Theory postulate stating average particle kinetic energy is directly proportional to absolute Kelvin temperature ($KE = \frac{1}{2}mv^2 \propto T$).

Maxwell-Boltzmann Distribution

A probability distribution of particle kinetic energies or speeds at a given temperature that broadens, flattens, and shifts rightward as temperature increases.

Van der Waals Equation of State

An equation modifying $PV = nRT$ for non-ideal gas behavior: $\left(P_{measured} + \frac{n^2a}{V^2}\right)(V_{measured} - nb) = nRT$.

Van der Waals Constant $a$

Parameter in the Van der Waals equation ($\text{atm}\cdot L^2/\text{mol}^2$) that corrects for intermolecular attractions pulling gas particles away from container walls.

Van der Waals Constant $b$

Parameter in the Van der Waals equation ($L/\text{mol}$) that corrects for the finite, excluded molar volume occupied by real gas particles.

Compressibility Ratio ($PV/RT$)

A quantitative ratio equal to $1.0$ for ideal gases, dipping below $1.0$ when intermolecular attractions dominate, and rising above $1.0$ when particle volume dominates.

Saturated Solution

A dynamic physical equilibrium state wherein the rate of solid solute dissolving equals the exact rate of dissolved solute precipitating.

Hydrophobic Chain Effect

The solubility phenomenon in long-chain alcohols where expanding non-polar hydrocarbon chains dominate over polar $-OH$ groups, restricting water solubility.

Interstitial Alloy

A metallic solution where small non-metal atoms occupy interstitial voids between host metal atoms, pinning layers to increase rigidity and decrease malleability.

Substitutional Alloy

A metallic solution where solute metal atoms replace solvent metal atoms of comparable atomic radius, preserving lattice layer sliding, malleability, and ductility.

Molarity ($M$)

A concentration unit defined as moles of solute divided by liters of solution ($M = \frac{n_{solute}}{V_{solution}}$), which varies with temperature due to thermal expansion.

Planck's Quantum Theory

Quantum theory stating that light energy is emitted in discrete packets according to the relation $E = h\nu = \frac{hc}{\lambda}$, where $h = 6.626 \times 10^{-34}\,J\cdot s$.

Ultraviolet / Visible Spectroscopy

Spectroscopy utilizing light in the $10\,nm - 750\,nm$ range to promote valence electrons between molecular orbitals ($\pi \rightarrow \pi^*$, $n \rightarrow \pi^*$).

Infrared (IR) Spectroscopy

Spectroscopy utilizing light in the $750\,nm - 1\,mm$ range to excite quantized molecular vibrational stretching and bending modes.

Microwave Spectroscopy

Spectroscopy utilizing radiation in the $1\,mm - 1\,m$ range to trigger transitions between molecular rotational states, strictly requiring molecules with a permanent dipole.

Beer-Lambert Law

A spectrophotometric equation establishing a direct linear relationship between absorbance and concentration: $A = \varepsilon\cdot b\cdot c$.