Unit 3: Properties of Substances and Mixtures Pt. 1

Flashcards covering intermolecular forces, phases of matter, properties of liquids, different types of crystals, and the ideal gas law from Unit 3 lecture notes.

Intermolecular Forces (IMFs)

Forces of attraction or repulsion that occur between neighboring particles (atoms, molecules, or ions).

Ion-ion forces

The electrostatic forces of attraction between oppositely charged ions within an ionic compound's crystal lattice. Strength increases with higher charge and smaller ion size.

Ion-dipole forces

Attractive forces between an ion and a polar molecule (which has a dipole moment). Strength depends on the charge of the ion and the polarity of the polar molecule.

Hydrated

A metal ion surrounded by many water molecules attracted to it.

Energy of hydration

Energy released in the process of a metal ion attracting to water molecules, which increases as the ion's charge increases and its size decreases.

Solvated

Ions attracted to other polar solvents, surrounded by solvent molecules.

Energy of solvation

Energy released in forming attractions between ions and polar molecules in a solvent.

Dipole-Dipole Forces

Attractive forces between neighboring polar molecules. Strength depends primarily on the polarity of the molecules (bigger dipole moment means stronger forces).

Polarity (Molecular)

The permanent dipole moment on a molecule created by the unequal sharing of electrons in covalent bonds due to the electronegativity difference and the shape of bonded atoms.

Hydrogen Bonding

A special, strong type of intermolecular force occurring when a hydrogen atom bonded to a highly electronegative atom (F, O, or N) is attracted to another electronegative atom (F, O, or N) in a neighboring molecule.

Dipole-Induced Dipole Forces

Forces created when a polar molecule induces a temporary dipole in a neighboring nonpolar molecule by distorting its electron cloud.

Polarizability

The ease with which the electron cloud of an atom or molecule is distorted by an outside influence, thereby creating a temporary induced dipole. Molecules with larger, more extended electron clouds have higher polarizability.

Induced Dipole-Induced Dipole Forces (London Dispersion Forces or Dispersion Forces)

Weak attractive forces that occur between all atoms and molecules due to temporary, fluctuating dipoles caused by instantaneous imbalances in electron distribution.

Kinetic Molecular Theory of Gases

A model stating that gas molecules/atoms are widely separated, have negligible intermolecular forces, are in continual random motion, and their kinetic energy is determined only by the gas temperature.

Enthalpy of Vaporization (ΔHvap)

The energy required at constant pressure to vaporize one mole of a liquid substance.

Enthalpy of Condensation

The energy released when one mole of a gas condenses into a liquid, equal in magnitude but opposite in sign to the enthalpy of vaporization.

Evaporation

The process where some particles at the surface of a liquid gain enough energy to escape into the gas phase.

Equilibrium Vapor Pressure

The pressure exerted by the vapor in equilibrium with its liquid phase at a given temperature, measuring the tendency of a molecule to escape the liquid phase.

Volatility

A measure of how readily a substance vaporizes, indicated by a higher equilibrium vapor pressure at a given temperature.

Boiling

The process where the average particle in a liquid has sufficient kinetic energy to escape the liquid phase, forming bubbles of vapor within the liquid body.

Boiling Point

The temperature at which the vapor pressure of a liquid equals the external atmospheric pressure.

Normal Boiling Point

The boiling point of a liquid when the external pressure is exactly 1 atmosphere.

Surface Tension

A property of liquids caused by the net inward attractive forces on surface molecules, leading to phenomena like a pin floating on water or spherical liquid drops.

Capillary action

The ability of a liquid to flow in narrow spaces against the force of gravity, resulting from a competition between adhesive forces (liquid-wall) and cohesive forces (liquid-liquid).

Meniscus

The curve in the upper surface of a liquid column, formed by capillary action.

Viscosity

A liquid's resistance to flow, determined by its intermolecular forces and the size/shape of its molecules.

Allotrope

Each of two or more different forms of an element characterized by different bonding within the molecules and different properties (e.g., diamond and graphite for carbon).

Covalent Network Crystals

Crystalline structures where atoms are held together by an extended network of strong covalent bonds throughout the entire structure (e.g., diamond, quartz). They are very hard, rigid, and have extremely high melting points.

Molecular Crystals

Crystalline structures formed from discrete covalent molecules held together by relatively weak intermolecular forces (e.g., ice, dry ice, iodine). They typically have low melting points and do not conduct electricity.

Ionic Crystals

Crystalline structures comprised of positive and negative ions held together by strong electrostatic ionic bonds (e.g., NaCl, CaF2). They have high melting points and conduct electricity only in molten or aqueous states.

Metallic Solids

Crystalline structures composed of metal atoms held together by metallic bonds, often described as a 'sea' of delocalized electrons. They are typically malleable, ductile, good conductors of electricity and heat, and have variable melting points.