ch 5 Flashcards
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!
relationship between temp and speed
temp=avg KE
avg KE : speed
so
as temp increases, diversity of speed increases (wider distribution of particle speeds)
relationship between particle size and speed
the smaller the particles, the wider the distribution of speeds
larger mass=slower particles so more narrow dis of speed
