phyparlec Flashcards
EXTENSIVE property
A property that depends on the amount of matter in a sample
mass
volume
length
INTENSIVE property
Property that does not depend on the amount of substance present.
- color
- temperature
- pressure
- density
- viscosity
- surface tension
- specific gravity
ADDITIVE
depends on the amount or size of the substance in a molecule
CONSTITUTIVE
depends on the arrangement/structure within a molecule
COLLIGATIVE
depends on the number of SOLUTE or concentration in solution
conversion
1mmHg = 1Torr
1atm = 760mmHg
1atm = 14.7 psi
1atm = 29inHg
Boyle’s Law
the Pressure and Volume of a gas are INVERSELY PROPORTIONAL
at constant temperature
P1V1 = P2V2
Charle’s Law
the Volume of the gas is
DIRECTLY PROPORTIONAL to its Temperature at constant pressure
V1/T1 = V2/T2
Avogadro’s Law
equal Volume of gases at the same temperature and pressure , contain equal Number of molecule
V1/N1 = V2/N2
Gay Lussac’s Law
Pressure of gas is directly proportional to its absolute Temperature at constant volume
P1/T1 = P2/T2
Combined Gas Law
equation that relates pressure, volume, and temperature of gas
(P1V1)/T1 = (P2V2)/T2
Partial Pressure
the pressure exerted by a single component in a mixture of gases
Dalton’s Law
the total pressure of a gas mixture is equal to the sum of the partial pressures of each individual gas
P(total) = Pa + Pb + Pc
Raoult’s Law
the vapor pressure in a solution or mixture is equal or identical to the vapor pressure of the pure solvent multiplied by its mole fraction in the solution
Ideal Gas Behavior
Van Der Waals Equation
an equation that corrects the Ideal Gas Law for intermolecular forces and molecular volume
(P + n2a/V2)(V-nb) =nRT
a/V2 accounts for the internal pressure per mole
b accounts for incompressibility of molecules, that is excluded (4x the molecular volume)
non ideality is greater when the gas is compressed
pressure is high and temperature is low
Molar Heat of Fusion
The amount of heat required to convert a unit mass of a solid into a liquid at its melting point.
Heat lost or gained in the conversion involving solid and liquid by 1 mole of substance
- S→L
- heat is absorbed therefore, + Hfusion
- L→S
- heat is released therefore, - Hfusion
Molar Heat of Evaporation
The amount of heat required to convert one mole of a substance from liquid to gas at constant temperature
Heat required for the conversion involving liquid and gas by 1 mole of a substance
- L→G
- heat is absorbed therefore, + Hvap
- G→L
- heat is released therefore, - Hvap
Gibb’s Phase Rule
determines the relationship for the least number of intensive variables that can be changed without changing the equilibrium state of the system
A principle that relates the number of phases in a system to the number of components and degrees of freedom, expressed as F = C - P + 2.
Phase
A homogenous part of the system, physically separated by distinct boundaries
Independent Variables
do not depend on the amount of matter present in the phases
Degrees of Freedom
the number of independent parameters that defines its configuration
critical pressure
pressure needed to liquify gas
also the highest vapor pressure that the liquid can have
critical temperature
temperature beyond which the liquid no longer exists
The further a gas is cooled below its critical temperature, the less
pressure is required to liquefy it.
For water, critical temp is 647K and pressure is 218 atm.
Eutectic Point
The temperature and composition at which two or more phases coexist in equilibrium.
Phase Diagrams are valuable for
- interpreting interactions between two or more components
- purity
- melting point depression (determination)
- possible liquification at room temperature
- formation of solid solutions
- formation of coprecipitates and other solid state interactions
KINETIC MOLECULAR THEORY OF GASES
Gasses are composed of particles called atoms or molecules, the total volume of which is so small as to be NEGLIGIBLE in relation to the volume of space in which the molecules are confined.
Gasses do not attract one another, but instead move with complete INDEPENDENCE.
- The particles exhibit continuous RANDOM MOTION owing to their kinetic energy. The average kinetic energy is directly proportional to the absolute temperature of the gas.
- E= 3/2RT
Gas molecules exhibit PERFECT ELASTICITY; that there is no net loss of speed or transfer of energy after they collide with one another and with the molecules in the walls of the confining vessel, which latter effect accounts for gas pressure.
- High Temperature, High Kinetic Energy
- Low pressure, Low Kinetic Energy
Diffusion
Process by which gas particles spread out in response to a concentration gradient.
- Influenced by root mean square velocity
- Lighter particles diffuse faster than heavier ones