General Chemistry Ch 8. Gas Phase Flashcards
Gas phase
Least dense phase of matter, fluids, conform to the shape of their container, easily compressible
Pressure equivalencies
1 atm = 760 mmHg = 760 torr = 101.325 kPa
Simple mercury barometer
Measures incident (usually atmospheric) pressure, as pressure increases, more mercury is forced into the column increasing its height, as pressure decreases, mercury flows out of the column under its own weight, decreasing its height
Standard temperature and pressure
273 K and 1 atm
Ideal gases
Assume negligee mass and volume of gas molecules, equimolar amounts of two gases will occupy the same volume at the same temp and pressure, at STP, one mole of ideal gas occupies 22.4 L
Avogadros principle
A special case of the ideal gas law for which the pressure and temperature are held constant, it shows a direct relationship between the number of moles of gas and volume
Boyles law
Special case of the ideal gas law for which temperature and number of moles is held constant, shows an inverse relationship between pressure and volume
Charles law
Special case of the ideal gas law for which pressure and number of moles is held constant, shows a direct relationship between temperature and volume
Gay-Lussacs Law
Spacial case of the ideal gas law for which volume and number of moles are held constant, shows a direct relationship between temperature and pressure
Combined gas law
Combination of Boyles, Charles, and gay-lussacs laws, shown and inverse relationship between pressure and volume along with direct relationship between pressure and volume with temperature
Daltons laws of partial pressures
States that individual gas components of mixture of gases will exert individual pressures in proportion to their mole fractions, the total pressure of a mixture of gases is equal to the sum of the partial pressures of the component gases
Mole fractions
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Henrys laws
States that the amount of gas dissolved in solution is directly proportional to the partial pressure of that gas at the surface of a solution
Kinetic molecular theory
Attempts to explain the behavior of gas particles, makes the following assumptions:
Gas particles have negligible mass, gas particles do not have intermolecular attractions or repulsions, gas particles undergo random collisions with each other and the walls of the container, collisions between gas particles and the walls of the container are elastic, the average kinetic energy of the gas particles is directly proportional to temperature
Grahams law
Describes the behavior of gas diffusion or effusion, stating that gases with lower molar masses will diffuse oe effuse faster than gases with higher molar masses at the same temperature
Diffusion
The spreading out of particles from high to low concetrations
Effusion
Movement of gas from one compartment to another through a small opening under pressure
Real gases
Deviate from ideal behavior under high pressure, low volume, or low temperature conditions
Moderately high pressure, low volume, low temperature real gases
Will occupy less volume than predicted but the ideal gas law because the particles have intermolecular attractions
Extremely high pressure, low volume, low temperature real gases
Will occupy more volume than predicted by the ideal gas law because the particles occupy physical space
van der Waals equation of state
Used to correct the ideal gas law for intermolecular attractions and molecular volume
Ideal gas law equation
PV = nRT
Density of a gas equation
rho = m/V=PM/RT
Combined gas law equation
P1V1/T1 = P2V2/T2
Avogadros principle equation
n/V = k or n1/V1 = n2/V2
Boyles law equation
PV= k or P1V1=P2V2
Charles law equation
V/T=k or V1/T1=V2/T2
Gay Lussacs law equation
P/T=k or P1/T1=P2/T2
Daltons law total pressure from partial pressures equation
PT = PA+PB+PC…
Daltons law partial pressure from total pressure equation
PA=XA*PT
Henrys law equation
[A] = k_H*P_A or [A1]/P1=[A2]/P2 = k_H
Average kinetic energy of a gas equation
KE = 1/2mv^2=3/2K_b*T
Root mean square speed equation
u_RMS = sqrt(3RT/M)
Grahams law equation
r1/r2 = sqrt(M2/M1)
van der Waals equation of state
(P+n^2*a/V^2)(V-nb) = nRT