Gas laws 2 Flashcards
Avagadro’s law states
“equal volumes of gases at the same temperature and pressure contain the same number of molecules regardless of their chemical nature and physical properties”.
Avogadro’s law states that one mole of an ideal gas occupies a volume of 22.4 liters at 1 atm and 0 C
Avagadro’s #
6.023 x 10 `23 particles
What is a mole
It is the number of molecules of any gas present in a volume of 22.4L and is the same for the lightest gas (hydrogen) as for a heavy gas such as carbon dioxide or bromine,
one Mole of an ideal gas occupies?
22.4 Liters at Standard temperature and pressure
If all gases are kept the same what would that look like
Volume 22.4 L, Pressure 1 atm, Temperature 0C, Mass would vary, Gas molecules would be 6.022 X 10 ‘23
2 moles occupy how much volume
44.8 liters because 1 mole occupies 22.4 liters
What is the ideal Gas Law formula
PV=nRT
Pressure is atm, Volume in liters, nunber of moles, R=gas constant, Temperature in kelvin,
Define ideal gas law
it describes the behavior of an ideal gas under all conditions.
as a cylinder of compressed gas empties, the pressure in the cylinder falls. What law applies?
The ideal gas law (PV=nRT)
The cylinder will have constant volume
the number moles of gas decreases as the gas exits the cylinder, so pressure decrease,
Dalton’s law of partial pressures
It is the sum of the partial pressure of each of the component gases
Example.
O2-20.9 + N2 78.1 + Ar+H2O+CO2= Air 101.3
p1+p2+p3…….= P total
How do you calculated partial pressure, whos law does this use
(% concentration/100) X total pressure
Dalton’s law of partial gases,
–This is basic math– If something is X% of the total gas then it will equate to X% of the total pressure (Not very hard)
What is standard atmospheric pressure?
760 mmHg
atm is 710 mmHg // O2 is at 2L // N20 is at 4L , What is the partial pressure of each gas?
- 3333 X 710= 233 for O2
0. 6667 X 710 = 474 for N2O
What are the pressures for our volatile agents?
Sevoflurane 157 mmHg
Isoflurane 238 mmHg
Halothane 243 mmHg
Desflurane 669 mmHg
You have a container of O2 that is 100% O2, and you add iso, what is the % of O2 and the % of iso in the flask above the liquid
760-238= 522
O2=68.6%
Iso= 31.3 %
how do you calculate % volatile agent?
(saturated vapor pressure of volatile agent/760) X 100
explain Nitrous Oxide
Colorless odorless
it can support combustion
critical temp is 36 C
It exists as a vapor in equilibrium with its liquid phase
As vapor is taken off, the tank equals out its vapor and liquid form
A full E cylinder contains 1590 liters
Nitrous gauge pressure is 750 psi
the pressure will not change as the gas is used until the liquid is used up
If the pressure is depleting it is almost used up
When the pressure begins to decline there is only 400 liters left of N2O
If you are delivering 6% desflurane in O2, N2 and air which are all at 2L, what is the % for each?
6%-100 is 94, then 94 X /3 gives you 31.3%
A N2O tank has a pressure of 700 do I care?
Yes it is below 750, therefore all the liquid is gone and it is nearing depletion
What 2 gases are in Liquid form
N2O and CO2
What should you know about an O2 tank
2L min, when will I run out of O2 on a full tank?
it will always exist in a gas state around room temp
O2 cylinders are filled to gauge pressue of 1900-2200 psi
they contain 660 liters
1000psi would indicate that an O2 tank is 330 liters
As long as you know the volume you can calcuate how fast you will run out of O2,
330min
