Gas Laws

Front 1

Pneumonic to remember gas laws.

Back 1

These Gas Problems Become Very Complex.
(each letter is written around the triangle in order for a toal of 6. It gives you which persons law relates to which physical property. )

Front 2

Gay Lussacs

Back 2

Temp directly proportional to Press at constant V.
P/T=K (a constant)

Front 3

Boyles

Back 3

P is inversly related to volume at constant T
P*V=K (a constant)
* A syringe compresses gas as the plunger is pushed. Pressure goes up as volume goes down.

Front 4

Charles

Back 4

Temperature is porportional to volume at a constant pressure.V/T=K
*When temp increases volume of gas increases.

Front 5

Generalized ideal Gas law

Back 5

PV=nRT
*as n decreases in a cylinder P decreases (v is unchanging in cyliner)

Front 6

Daltons theory of partial pressure.

Back 6

Total pressure in a mixture of gasses is teh sum of the individual pressures. Each gas has a partial pressure calculated by multipying the percent times the atmospheric pressure.

Front 7

What is the partial pressure of N2O and O2 if given in a 70/30 mixture?

Back 7

.7*760=532
.3*760=228

Front 8

What is the partial pressure of CO2 if the endtidal gas concentration is 5%?

Back 8

.05*760=38 mmHg.

Front 9

Avagadros hypothesis:
(Define Standard Temperature Pressure (and Volume))

Back 9

One mole of gas at standard temperature (0 celcius) and standard pressure (1 atmosphere) occupies a volume of 22.4 liters.

Front 10

How much volume is there in 2.4 moles of a gas?

Back 10

2.4*22.4=53.76

Front 11

Adiabatic

Back 11

in cylinders since volume is constant (PV=nRT) when you quickly change the n and P, temp also changes to compensate, Increases with pressure rise, decreases with pressure drop.

Front 12

Ficks Law

Back 12

Diffusion:
diffusion is directly proportional to the concentration gradient.

Front 13

Flow through a tube

Back 13

Is not diffusion: it is bulk migration of molecules focibly propelled.

Front 14

Grahams law

Back 14

Effusion
"the heavier a gas the slower it moves."
Rate1/Rate2=Sqrt(M2/M1)
(rate =rate of effusion M= molecular weight of Gas.

Front 15

Henry's Law

Back 15

Number of gas molecules dissolved in a liquid varies directly with the partial pressure of a gas overlaying the liquid.
"Henry says the colder it is the more gass can pass"
Cooler liquids accept more gas than warmer liquids.
Think Fevers vs. Hypothermia.

Front 16

Henry law application:
Calculate the ammount of O2 that will dissolve in 100 ml of blood if PaO2 is 300 mm hg.

Back 16

.003*300= 0.9 ml O2/ 100 ml of blood (not including the O2 on hemoglobin.)

Front 17

Henry law application:
Calculate the ammount of CO2 that will dissolve in 100 ml of blood if PaCO2 50 mm Hg.

Back 17

0.067* 50=3.35 mm Hg.

Front 18

What causes turbulent flow?

Back 18

1. high velosity
2.rough surface (ie corregated wall)
3.Kinks, bends, narrowing. (ie greater than 25 degrees)
4.Fluids through an orifice.

Front 19

Hagen Poiseuille Equation

Back 19

Q=(pi R^4/8n)*Delta P/L
n=viscosity
P=pressure gradient from beginningn to end of tube,
L=length of tube.
r=radius of tube.

This equation (don't memorize, just understand, shows us why the following occurs:
*A asthmatic can't move air (radius^4)
*Put on a pressure bag to rapidly infuse blood
*Shorter IV tubing = faster infusion.
*Heliox is easier to breathe (fluid viscosity)
*Crystaloids infuse faster than colloids (fluid viscosity)

Front 20

Reynolds

Back 20

just remember a reynolds nuber >1500 = turbulent flow.