Liquids and Solids Flashcards
Gas
Conforms to the volume and shape of the container Continual motion Low density Easily compressed to smaller volume Weak intermolcular forces
Liquid
Conforms to the shape of the container
Sliding motion of particles past one another
Moderate density
Small ability to be compressed
Miscibility
The degree to which two liquids can mix
Immiscible
Molecules that repel each other due to their polarity difference not allowing mixing
Emulsion
Under extreme conditions 2 immiscible liquids form a homogeneous mixture of discrete particles too small to be seen
Solid
Defined volume and shape
Particles in a fixed position (vibrational energy)
High density
Difficult to compress
Crystalline solid
Possesses an ordered structure of 3-D geometric arrangement with repeating patterns of atoms, ions, or molecules
Amorphous solid
No ordered 3-D arrangement of atoms
Ionic solids
Aggregates of positively and negatively charged ions High melting & boiling points Poor electrical conductivity Strong electrostatic interactions Ions immobile
Metallic solids
Metals atoms packed together as closely as possible
High melting & boiling points
Strong covalent attractions
Unit cells
The smallest repeating units that compose the large crystalline structure
Simple cubic, body-centered cubic, face-centered cubic
Each point represents the exact same atom/ion
Specific heat
The amount of heat required to raise a unit mass of a substance 1 K or 1 C
Latent heat of transformation (Hl)
The amount of heat needed to change the phase of 1 kg of a substance
Heat of transformation
Temperature of substance remains constant, the heat gained/lost is related to the amount of material that changes phase
Q = mHl
Heat of fusion
Phase change from liquid to solid at the melting-point temperature
Heat of vaporization
Phase change from liquid to gas at the boiling-point temperature
Evaporation/vaporization
Molecules with enough energy leave the liquid phase and escape into the gaseous phase
Cooling process
Condensation
Escaping evaporated molecules trapped by a cover exert a countering pressure, forcing some of the gas back into the liquid phase
Gas-liquid equilibraium
Between evaporation and condensation
Vapour pressure
The pressure that a gas exerts over the liquid
Increases as temperature increases
Boiling point
The temperature at which the vapour pressure of a liquid equals the external pressure
Fusion
Melting
Transition from solid to liquid
Atoms in solid phase absorb enough energy to break down the 3-D structure
Freezing
Solidification, crystallization
Transition from liquid to solid
Sublimation
Transition from solid to gas
Deposition
Transition from gas to solid
Phase diagram
Depicts the phases and phase equilibria of a substance at defined temperatures and pressures
Triple point
The intersection of the freezing/melting line, vaporization/condensation line and sublimation/deposition line where all three phases are in equilibrium
Critical point
The temperature and pressure above which the liquid and gas are not possible
Supercritical fluids exist
Colligative properties
Physical properties derived solely from the number of particles present not their nature
Freezing-point depression
Solute particles lower the temperature at which molecules can align themselves into a crystalline structure, lowering the freezing point
Boiling-point elevation
The boiling point of a liquid will be higher when another compound is added
van’t Hoff factor
i
Accounts for the number of particles that dissociate from the original molecule
Osmotic pressure
The minimum pressure which needs to be applied to a solution to prevent the inward flow of its pure solvent across a semipermeable membrane
Raoult’s Law
The partial pressure of each component of an ideal mixture of liquids is equal to the vapour pressure of the pure component multiplied by its mole fraction in the mixture
