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Graphs, volume versus pressure
volume versus pressure is 1/2 parabola
the volume varies directly with n (# of molecules) when T and P are constant.
Gay-Lussac
Fixed volume and moles are proportional to kelvin temp, P1/T1 = P2/T2
STP conditions
.08206 r
high temps, low pressures
When do gasses express ideal behavior?
Graham's Law of Effusion
velocity is inversely proportional to square root of its molar mass
volume vs moles
straight line positive slope?
half parabola
volume versus pressure
ratio of velocity
For example HCL & NH3
Volume versus Kelvin
straight line positive slop through origin
volume vs. number of moles
straight line vs positive slope through origin
Two state problem
Pin Vin/Pfin Vfin = Nin R Tin/Nfin R Tfin
q + w
equation of internal energy
Work=
P^v or nRT
^H=^E+PV
Change in Enthalpy
Energy
(physics) the capacity of a physical system to do work
Open System
A system in which both energy and matter can enter or exit
Closed System
A system containing a fixed amount of matter; it can still exchange energy with the surroundings.
Isolated System
A system that has are no energy transfers between that system and its surroundings.
heat absorbed/^T
heat capacity
1 cal
4.184 J
Elements in their standard state= 0
C(graphite), OV2(g), HV2(g), NV2(g), FV2(g), ClV2(g), BrV2(g), IV2(s), all metals(s), Hg(L)
F/A
Pressure
1kg/m*s^2=1N/m^2
1 Pa
Barometer
An instrument that measures atmospheric pressure
Manometer
Measures the height difference between gas and atmosphere
PV=K
Boyes law
V/T=k
Charles law
P/T=k
Gay-lussac's law
V/n=k
Avogardro's law
-P^v or nRT
Work
Specific Heat
Amount of heat needed to raise the temperature of 1kg of material 1 degree Celsius.
Molar heat capacity
heat absorbed/ mol substance X ^T
4.184 J
1 cal
PV= mRT/MM
Find molar mass
MM=DRT/P
Find Density
P
Pressure (760 mmHG,101.3kPa or 1 atm)
v
The index of refraction n is defined as , where c is the speed of light in air, and _______ is the speed of light in a material.
n
Nitrogen
R
(0.0821 atm) or (8.314kpa)
T
1/f
1 mol = 22.4 L
Ideal Gas law
the equation that expresses exactly how pressure (P), volume (V), temperature (T), and the number of particles (n) of a gas are related
Molar volume
the volume of 1 mole of an ideal gas; equal to 22.42 liters at standard temperature and pressure
Gay lussac's law
the law that states that the pressure of a gas at a constant volume is directly proportional to the absolute temperature
Combined gas law
P1V1/T1 = P2V2/T2
Grahams law of effusion
Rate1/Rate2= sr of MM2/sr of MM1
pressure
_______ is the measure of force exerted on a unit area of surface
Daltons law of partial pressure
Partial pressure is pressure of each gas in a mixture. Dalton's law of partial pressures is the total pressure of a gas mixture in the sum of the partial pressure of the component gas
Charles law
Volume and Temp.; V₁/T₁ = V₂/T₂
density is equivalent to...
M / V, MM / R to P / T (ratio)
Kinetic Energy equation
K.E. = 1/2(MM)u^2
Constant
horizontal motion is _______
Collisions are elastic/sticky
elastic (molecules do not stick to each other or the walls)
mu^2
measure of the energy of collision
What is gas pressure caused by?
collisions of molecules with the walls of the container- pressure increases with the energy and frequency of these collisions
u
average speed of a molecule
u^2
average of the squares of the speeds of all molecules
N/V or N:V
What ratio expresses the concentration of gas molecules in a container?
the greater collision frequency, the higher pressure
The more molecules in a volume, the greater/lower collision frequency, the higher/lower pressure
Nmu^2 / 3V
Pressure equals (variables N m u^2 V)
3RT / 2N(a)
Average Transitional Kinetic Energy
Average speed, u
(3RT / MM) ^1/2
(MMA / MMB) ^1/2
UB / UA = (at constant pressure and temperature; if speed is not a concern)
Gaseous diffusion
gas molecules move through space from a region of high concentration to one of low concentration (slow and complex process)
Gaseous effusion
the flow of gas molecules at low pressures through tiny pores or pinholes (simpler process0
Pressure unit
force per unit area
1 atm pressure = psi = kPa = mm Hg = Torr = bar
1 atm pressure = 14.696 psi = 101.325 kPa = 760 mm Hg = 760 Torr = 1.01325 bar
Psi stands for
pounds of force per square inch of wall
Mercury Barometer
what we use to measure atmospheric pressure. Invented by Evangelista Torricelli. At sea level it varies
Pascal (Pa) or Bar*
In the international system, the standard unit of pressure is
Newton
(kg*m)/(s*s)
75 pounds of pressure
1 sq. inch holds how much pressure?
What is atmospheric pressure?
Atmospheric pressure is actually gravitational pull, and the gravitational pull gets less as we move farther away from the Earth
We are hollow
why do we not feel the pressure weighing on us?
Ideal Gases
Imaginary Gases that perfectly fit all of the assumptions of the kinetic molecular theory
Real Gas
More polar gases
Conditions that make gases act like real gases
SI unit of pressure
newton/meter^2 = 1 pascal
1 atmosphere
101,325 Pascals (Pa)
Conversion factor from atm to torr
1 atm = 760 torr = 760 mmHg = 101.325 KPa
Barometer
First device used for measuring atmospheric pressure
Evangelista Torricelli, 17th century
Created the barometer, and in what century
Charles's Law
V1/T1 = V2/T2
Equal volumes of different gases at the same temperature and pressure contain equal numbers of molecules.
Standard Molar Volume states that
Equal volumes of all gases at the same temperature and pressure contain the same number of molecules.
M = dRT/P
Equation for molar mass of a gas
Gas Density Units
molar mass / volume
Density at STP
22.4 g/ Liter
Formula for density
D = MP/RT
Law of Partial Pressures
For a mixture of gases in a container,
How to use law of partial pressures
Two gases in a container. Use ideal gas laws to find pressure of each individually. add those together to get total pressure.
Kinetic Molecular theory
states that submicrocopic particles of all matter are in constant, random motion
KE 1/2 mv^2
Formula for kinetic energy of gas
KE = 3/2 RT
formula for average kinetic temperature
Diffusion
The mobility of a gas through another substance. Particles will diffuse faster if they are light weight, if they are gaseous, temperature increases.
Rate of diffusion
rate of different gases mixing
Effusion
process of a gas leaking out a small opening. same prop as diffusion
rate = (M)^(-1/2)
Grahams law for rates of effusion and diffusion
Absolute Zero
0 Kelvin, no movement of particles
8.312 L kPa/ mol K
Proportionality constants for Ideal gas law Kilopascals
atm
0.08206 L atm/ mol kPa
8.3145 J/mol K
Joules (use this in KE formulas)
Mole Fraction
Xa=mol A/total mol