ch 5 Flashcards
(26 cards)
density equation
D= PM/RT
total pressure equation given partial
Ptotal= PA + PB +…
equation for pressure
pressure=force/area
small areas-higher P
larger areas-lower P
barometer
measures P of atm
more collisions (force) means
higher pressure
converting mmHg/torr to atm and kPa
1 atm= 760 mmHg/torr
1 atm= 101.3 kPa
combined gas law
P1V1/n1T1 = P2V2/n2T2
must be in K
must be in atm
what is R
.08206
boyles law
P1V1=P2V2
V/1:1/P
Volume and pressure are indirectly proportionate
BECAUSE
when volume decreases, gas particles collide more often, increasing force, and increasing pressure
Charles’ law
relationship between V and T is directly proportional
V1/T1=V2/T2
must be in K
Avogadro’s Law
relationship between volume and amount in moles directly proportional
V1/n1=V2/n2
ideal gas law
PV=nRT
just combines Boyle, Charles, and Avogadro’s Laws
higher molar mass means… ____density
increasing molar mass increases density
PM/RT=D
how to find molar mass of a gas
- measure mass and volume under conditions of known temp and P
- using ideal gas law, find number of moles
- calculate molar mass by dividing mass by number moles
mole fraction
nA/ntotal= Xa
Xa + Xb + Xc +….= ALWAYS 1
equation to find Ptotal given partial pressures
Ptotal= (na + nb + nc +…)(RT/V)
under same temp and volume conditions
equation to find partial pressure given either mole fraction or total pressure
Pa=Xa(Ptotal)
Xa is mole fraction (moles/total moles)
equation of KE
KMT
KE= 1/2mv^2
m=mass (kg)
v=velocity (m/s)
KE=kinetic energy (J)
at a given temp, all gases have…
the same average KE
ideal gas conditions
PLIGHT
low pressure
high temp
-assume ideal gas at STP
-lower volume
molar volume
m^3/mol
as P in, molar volume decreases
IFA increase effect on gas
-temp
-pressure
-ideal?
-IFA increases as temp decreases
-pressure de as IFA inc (less collisions)
-more ideally because lower pressure
PV/RT =1 vs not =1
what about >1 and <1?
PV/RT= 1 means ideal
PV/RT not =1 means real/nonideal
PV/RT >1 = particle volume is predominating ideal behavior
PV/RT <1 = IFAs predominate ideal behavior (low pressure)
if PV/RT=n=1 then…
IDEAL GAS!
