CHM135 Term Test 1 Review

Solubility of Molecular Solids

Due to intermolecular forces, it will only dissolve in a solvent with the same intermolecular forces.

Spectroscopy

The study of interaction between electromagnetic radiation and matter.

Waves Characteristics

Wavelength, frequency, and amplitude (brightness).

Electronic Structure Evolution

Analyzing the probability of finding the electron instead of pinpointing its exact location.

Electron Shielding and Energy Difference

Electron shielding in multi-electron atoms gives rise to energy difference among 3s, 3p, and 3d orbitals.

Amorphous Solids

More random systems with a poorly defined shape.

Solubility of Metals

Due to metallic bonding, it is only soluble in metal liquids.

Solubility of Ionic Solids

Due to ion-ion electrostatic interactions, it will only dissolve if solvent dipole-dipole interactions are strong enough.

Raoult's Law for Non-Volatile Solution

Vapour Pressure of Solution = Mole Fraction of Solvent * Vapour Pressure of Solvent

Photoelectric Effect

Kinetic energy increases linearly with frequency. Number of ejected electrons increase with intensity, KE does not.

Binding Energy

The amount of energy required to disintegrate a system of particles into separate parts. Same as the work function.

Planck's Explanation

Energies of oscillating atoms in a heated solid were multiples of a small quantity of energy. Energy is not continuous, and radiation is emitted in discrete packets called photons.

Work Function

The minimum energy needed to eject an electron. KE = hf - W, W = y-intercept, threshold frequency = x-intercept.

Planck's Equation

E = hf. h = 6.62 x 10^-34

Einstein's Equation

E = hc / lambda, h = 6.62 x 10^-34

Atomic Line Spectra

Indicates the properties of atoms causing certain lights. Excited atoms give off discrete frequencies which lines at specific points.

Bohr Model of the Atom

Electrons orbit the nucleus in fixed paths, each electron has certain allowed orbits or energy levels, and energy is quantized.

DeBroglie's View on Light

Light may behave like waves and particles, leading to the wave-particle duality theory.

Energy of Hydrogen Orbitals

En = -k / n^2, k = 2.18 x 10^-18

Pauli Exclusion Principle

No two electrons can have the same 4 quantum numbers.

Aufbau Principle

Electrons fill the lowest energy levels first before moving on to higher levels. Also refers to the formation of ionic compounds.

Hund's Rule

Every orbital in a sub-shell is single-occupied with an electron before being doubly occupied.

Heisenburg Uncertainty Principle

We cannot know about both an electron's momentum and position with great precision simultaneously.

Quantum Numbers

n is the principal quantum number (defines size and energy level), l is the angular momentum quantum number (defines 3-d space of orbital), m is the magnetic quantum number (defines spatial quantum number).

Effective Nuclear Charge

The net positive charge experienced by an electron.

Periodic Trends of Atomic Radii

Atomic radii decreases as you move across the periodic table, and increases as you move down.

Pressure Definition

The force exerted per unit area.

Atmospheric Pressure

The mass of air exerted on the earth's surface.

Boyle's Law

Volume is inversely proportional to pressure.

Charle's Law

Temperature is proportional to volume.

Gay-Lussac's Law

Temperature is proportional to pressure.

Avagadro's Law

Volume is proportional to the number of moles.

Density of a Gas Measurement

PM/RT

Dalton's Law of Partial Pressures

Total pressure exerted by a mixture of gas is equal to the sum of the partial pressures of the gas.

Van der Waals Equation

(P + n^2a/V^2) (V - nb) = nRT

Surface Tension

The amount of energy required to expand a liquid surface.

Capillary Action

The rising of a liquid in narrow space against the pull of gravity.

Forces Acting on a Liquid in a Container

Cohesive Forces - between molecules, and Adhesive Forces - between molecules and container.

Viscosity

The resistance of a liquid to flow, related to intermolecular forces.

Phase Changes Dependence

Intermolecular forces draw particles together, and kinetic energy pushes particles away.

Entropy

Property related to the number of equivalent energy states in a system.

Gibbs Free Energy

Describes if a reaction will occur spontaneously. If G is negative, it will occur; if G is positive, it won't.

Vapour Pressure

The pressure of a gas in equilibrium, co-existing with its liquid or solid form at a specific temperature.

Crystalline Solids

Highly ordered systems with a well-defined shape.

Atomic Solids Properties

Low melting points, noble gases held together by single electrons by dispersion forces.

Molecular Solids Properties

Relatively low melting points, molecules held together by intermolecular forces.

Covalent Network Solids Properties

Very high melting points, atoms held together by covalent bonds.

Metallic Solids Properties

Various melting points, high electrical and thermal conductivity, malleable, and ductile.

Ionic Solids Properties

Very high melting points, held together by electrostatic interactions, low electrical conductivity in solids, brittle, and hard.

Packing

The maximization of intermolecular interactions by packing the particles as close as together.

Types of Packing

Simple-cubic, Body-centered cubic, Hexagonal-closest packing, and Cubic-closest packing.

Simple-Cubic Packing

All identical layers lined up in stacks and rows, 52 percent efficiency.

Body-Centered Packing

Spheres in layers are offset such that spheres in one layer fit into the depression into adjacent layers, 68 percent efficiency.

Hexagonal-Closest Packing

Two alternating hexagonal layers are offset so that the spheres of one layer sit in the triangular depressions of the other layers, 74 percent efficiency.

Cubic-Closest Packing

Three alternating layers that are offset so that they fit into the depression of the adjacent layers, 74 percent efficiency.

Unit Cell

Smallest unit from which the entire pattern can be made, used to describe crystal packing.

Coordination Numbers

The number of nearest neighbors surrounding a molecule, not always in the same unit cell.

Triple Point

Point where the 3 boundary lines meet and all 3 phases of a substance exist.

Dependence of Boiling and Freezing Points

High dependence for boiling point (pressure pushes molecules together), and low dependence for freezing point.

Critical Point

The highest pressure where a gas can exist and the highest temperature where a liquid can exist.

Supercritical Fluid

A single, dense fluid, gas/liquid hybrid, exists past the critical point.

Solute Dissolution

Solute-solute and solvent-solvent intermolecular forces must be overcome.

Solubility of Network Solids

Due to covalent bonds, the forces cannot be overcome, and therefore, it is insoluble in all compounds.

Henry's Law

Describes the solubility of a gas in a liquid, where Solubility = k * Vp.

The Bends

The formation of gas bubbles from a liquid due to a rapid decrease in pressure, causing obstruction of blood.

Colligative Properties

Solution properties that only depend on the concentration, and not the intermolecular forces, of solute particles.

Vapour Pressure Lowering

The addition of a non-volatile solution decreases the vapour pressure, as it will not evaporate.

Entropy of Non-Volatile Solution

The change in entropy from solution to gas is smaller, so it's less favored, resulting in a lower vapour pressure.

Raoult's Law for Volatile Solution

Vapour Pressure of Solution = Vapour Pressure A Mole Fraction A + Vapour Pressure B Mole Fraction B

Ideal Solutions

Solutions that obey Raoult's Law.

Boiling Point Elevation

A solute increases the boiling point of a solution. Change in Boiling Point = Kbmi.

Van't Hoff Factor

i = moles of particle of solution / moles of solute dissolved

Freezing Point Depression

A solute decreases the freezing point of a solution. Change in Freezing Point = -Kfmi.

Osmotic Pressure

The pressure that must be applied to the solution to prevent osmosis from a sample of pure solvent. Osmotic Pressure = MiRT