Chemistry Chapter 10: Liquids and Solids

Flashcards on Liquids and Solids, covering intermolecular forces, properties of liquids, phase transitions, phase diagrams, solid states, and lattice structures.

van der Waals forces

Attractive forces between neutral atoms and molecules.

Ion-dipole attraction

Electrostatic attraction between an ion and a molecule with a dipole.

Dispersion forces (London Forces)

Temporary polarity in molecules due to unequal electron distribution that leads to attractions

Dipole-dipole attractions

Permanent polarity in the molecules due to their structure that leads to attractive forces.

Hydrogen bonds

An especially strong dipole–dipole attraction that results when H is attached to an extremely electronegative atom (O, N, or F).

Factors Affecting Magnitude of Induced Dipole

Volume of the electron cloud, Larger molar mass = more electrons = larger electron cloud = increased polarizability = stronger attractions, shape of the molecule, More surface-to-surface contact = larger induced dipole = stronger attraction

Viscosity

The resistance of a liquid to flow; Larger intermolecular attractions = larger viscosity

Surface Tension

The energy required to increase the surface area of a liquid or the force required to increase the length of a liquid surface by a given amount; Liquids with large intermolecular forces tend to have high surface tensions.

Capillary Action

Spontaneous rising of a liquid in a narrow tube when intermolecular forces exist.

Cohesive forces

Intermolecular forces among the molecules of the liquid.

Adhesive forces

Forces between the liquid molecules and their container.

Vaporization

The change from the liquid phase to the gas phase

Condensation

The change from the gas phase to the liquid phase.

Dynamic equilibrium

When two opposite processes reach the same rate so that there is no gain or loss of material.

Volatile liquids

Liquids that evaporate easily

Nonvolatile liquids

Liquids that do not evaporate easily

Vapor pressure

The pressure exerted by the vapor when it is in dynamic equilibrium with its liquid.

Normal boiling point

The temperature at which the vapor pressure of the liquid = 1 atm.

Heat of vaporization (ΔHvap)

The amount of heat energy required to vaporize one mole of the liquid.

Fusion

Melting

Freezing

The opposite of melting.

Heat of fusion (ΔHfus)

The amount of heat energy required to melt one mole of the solid

Sublimation

Surface molecules with sufficient energy may break free from the surface and become a gas

Deposition

Capturing of vapor molecules into a solid

Phase diagrams

Describe the different states and state changes that occur at various temperature/pressure conditions.

Triple point

Temperature and pressure at which all three phases of a substance coexist.

Critical point

Specific temperature and pressure at which liquid and gas phases have the same density and are indistinguishable from each other

Supercritical fluid

Substance in a state that is above the temperature and pressure of the critical point.

Crystalline Solids

Molecules, atoms, or ions are in patterns with long-range, repeating order.

Amorphous Solids

Molecules, atoms, or ions do not have any long-range order.

Ionic Solids

Are composed of positive and negative ions that are held together by electrostatic attractions.

Metallic Solids

A uniform distribution of atomic nuclei within a “sea” of delocalized electrons.

Covalent Network Solids

Atoms are held together by a network of covalent bonds

Molecular Solids

Composed of neutral molecules.

Unit Cell

The basic repeating unit of the arrangement of atoms, ions, or molecules in a crystalline solid

Coordination Number

the number of other particles each particle is in contact with

Packing efficiency

The percentage of volume in the unit cell occupied by particles.

Tetrahedral hole

Tetrahedral hole Cation radius is about 22.5 to 41.4% of the anion radius

Octahedral hole

Octahedral hole Cation radius is about 41.4 to 73.2% of the anion radius

Cubic hole

Cubic hole Cation radius is about 73.2 to 100% of the anion radius

Bragg Equation

The interplanar distance (atomic spacings)

Valence band

The band of bonding molecular orbitals

Conduction band

The band of antibonding molecular orbitals

Energy Gap

The difference in energy between the valence band and conduction band

Doping

Adding impurities to the semiconductor’s crystal to increase its conductivity.

n-type semiconductors

Electron-rich impurities

p-type semiconductors

Electron-deficient impurity, resulting in electron “holes ” in the valence band.