Liquids & Solids Flashcards

Flashcards on Liquids and Solids based on Advanced Chemistry 30S lecture notes.

Translational Motion of Gases

Free motion.

Translational Motion of Liquids

Hindered motion.

Translational Motion of Solids

No motion.

Rotational Motion of Gases

Free motion.

Rotational Motion of Liquids

Hindered motion.

Rotational Motion of Solids

Hindered motion.

Vibrational Motion of Gases

Free motion.

Vibrational Motion of Liquids

Free motion.

Vibrational Motion of Solids

Free motion.

Intermolecular Forces

Forces of attraction between molecules or atoms.

Factors that ion-dipole interactions depend on

The magnitude of the ion’s charge, the magnitude of the dipole, and the distance between the ion and the dipole.

Dipole-Dipole Interactions

Forces of attraction between polar molecules. Weaker than ion-dipole forces, require close proximity of molecules. More polar molecules = stronger dipole-dipole interactions.

Hydrogen Bonding

A bond between hydrogen and an electronegative atom such as F, O, or N.

London Dispersion Forces

The motion of electrons within an atom or non-polar molecule can result in a temporary dipole moment.

Properties of Liquids

Very low compressibility, take the shape of their container, and high density (compared to gases).

Cohesive Forces

Forces between molecules within the liquid.

Surface Tension

The resistance of a liquid to an increase in its surface area.

Viscosity

The resistance of a liquid to flow.

Adhesive Forces

Forces between liquid molecules and their container.

Capillary Action

The spontaneous rising of a liquid up a tube, explained by strong adhesive forces between the liquid and the tube’s surface, as well as the strong cohesive forces between liquid molecules.

Crystalline Solids

Have a characteristic regular arrangement of particles.

Lattice

The positions of the particles in a crystalline solid.

Unit Cell

The smallest repeating unit of a crystal lattice.

Simple Cubic Unit Cell

8 atoms at the vertices of a cube.

Body Centered Cubic Unit Cell

Similar to simple cubic…with an extra atom in the center of the cube.

Face Centered Cubic Unit Cell

8 atoms at the vertices of a cube, with an additional atom in the center of each face of the cube.

Trigonal Hole

A hole formed by 3 atoms in a plane.

Tetrahedral Hole

A hole when a fourth atom is placed on TOP of three atoms.

Octahedral Hole

A hole formed by SIX atoms, four in a square plane, with one above and one below.

Hexagonal Closest Packed (HCP) Structure

An arrangement of atoms “A-B-A-B-A…”

Cubic Closest Packed (ccp) Structure

An arrangement of atoms “A-B-C-A-B-C-…” with a Face-Centered Cubic Unit Cell!

Substitutional Alloys

A metallic solid made up of a mixture of elements where some metal atoms are replaced by other metal atoms in a crystal lattice.

Interstitial Alloys

Small atoms fill some of the holes (interstices) between atoms in the crystal lattice.

Network Solid

An atomic solid where the atoms are bonded with strong “directional covalent” bonds.

Graphite

Where carbon atoms are covalently bonded together in planes held together by weak London Dispersion Forces, and slide off easily.

Diamond

Carbon atoms are bonded to four other atoms, in a tetrahedral geometry.

Heating Curve

A plot of temperature vs time.

Molar Enthalpy of Fusion (DHfus)

The energy (heat) required to melt one mole of a substance.

Molar Enthalpy of Vaporization (DHvap)

The amount of energy (heat) needed to boil one mole of water.

Sublimation

The conversion of a solid directly to a gas (without melting).

Molar Enthalpy of Sublimation (DHsub)

The energy needed to cause one mole of a solid to sublime.

Volatile

A liquid that has a very HIGH vapor pressure will evaporate very easily.

Normal Melting Point

Is defined as the temperature where the solid and liquid states have the same vapor pressure under conditions where the total pressure is 1 atmosphere (standard pressure).

Normal Boiling Point

Is defined as the temperature where the vapor pressure of a liquid is exactly one atmosphere (standard pressure).

Supercooling

Occurs when a liquid remains “liquid” when it is slowly cooled below its freezing point.

Superheating

Occurs if a liquid’s temperature rises above its boiling point before boiling starts.

Critical Point

The temperature and pressure at which the liquid and gaseous phases of a pure stable substance become identical.