Gas Slides Flashcards
In a gas/liquid interface, given thermodynamic properties of all these gases, some of these gases enter into the liquid and come right back out. When they come back out, they (gain/lose) energy.
lose
It takes them moments before they can exit the liquid again.
Gas is ______ in the liquid.
dissolved and have less energy
Arterial blood gas samples include O2 and CO2 values. For example, pO2(arterial) = 100 mmHg pressure is the dissolved state of the gas that delivers O2 from the blood to the tissues. True or false?
True
If you decrease the volume in a container with everything else being constant, the pressure _______.
increases
Constant temperature, the volume of a given mass of gas varies inversely with the absolute pressure.
Boyle’s Law
P1V1 = P2V2
Boyle’s Law
If we decrease the volume by half, then we increase the pressure by ___ fold if the temperature is held constant.
Which law is applied?
2 fold
Boyle’s Law
What is the containment volume of an E-cylinder?
4.8 - 5 Liters
1 atm = _____ kPa
101.33 kPa
What is the pressure of a full oxygen E-cylinder?
2200 psig
What is the volume of oxygen E cylinder?
625 Liters
Initial volume of air e-cylinder?
625 liters
Initial pressure of air e-cylinder?
2000 psig
If pressure reads 2200psig, what is the absolute pressure?
2200 psi + 14.7 psi = 2214.7 psia
At a constant pressure, the volume of a given mass of gas varies directly with the absolute temperature.
Charles’ Law
Charle’s Law
Charle’s Law
V1/T1 = V2/T2
At a constant volume, the absolute pressure of a given mass of gas varies directly with the absolute temperature.
Don’s Law
Don’s Law
P1/T1 = P2/T2
STP
T = 273 K, 0 C
P = 760 mmHg
RTP
T = 293 K, 20 C
P = 760 mmHg
BTP
T = 310 K, 37 C
P = 760 mmHg
In a mixture of gases, the pressure exerted by each gas is the same as that which it would exert if it alone occupied the container
Dalton’s Law
Celcius to Farenheit
9/5 C +32
If gases are separated out, each gas has ____ pressure.
decreased
Dalton’s Law
Vt/Pt = Vx/Px = Vy/Py
or Vx/Vy = Px/Py
The ratio of partial volumes to partial pressures is equal and equals the ratio of total volume to total pressure.
Vx/Vy = Px/Py
An etonox cylinder contains
50 kPa of N2O
50 kPa of O2
Dalton’s law in an air cylinder
21% O2
79% N2
What is the primary gas in the anesthesia delivery system, and is the carrier gas in many types of vaporizers, the driving gas for most ventilators, and the gas that controls the fail-safe mechanism (without adequate oxygen pressure all other gases are automatically turned off) inherent in all anesthesia delivery systems?
oxygen
ON EXAM
Prolonged high concentrations of oxygen may produce severe complications in some patients. There are five frequently discussed clinical conditions in which oxygen has been identified as the sole precipitating cause:
- 1) convulsions
- 2). toxicity (oxygen)
- 3)atelectasis
- 4) ventilation
- 5) Retrolental fibroplasia.
High concentrations of oxygen in zones of the lung with ___ ventilation: perfusion ratios will result in collapse (referred to atelectasis) of the alveoli, and a decrease in the ability to oxygenate the blood.
low
Nitrous gas provides amnesia and some analgesia and can be an anesthetic by itself. True or false?
False
Cryosurgical devices used by thoracic and ophthalmologic surgeons are powered by E cylinders of what gas?
nitrous oxide
There are a number of other gases used in the delivery of anesthesia for special purposes. Nitrogen is one of them. True or false?
False
Nitrogen is usually supplied to operating rooms for the sole purpose of providing a gas to drive pneumatic devices such as saws and drills.
__________ is a colorless gas that is a strong irritant to the respiratory tract in high concentrations.
Nitric Oxide (NO)
Ideal gas law
PV =nRT
Ideal gas law: P is
absolute pressure
Ideal gas law: n is
number of moles
Ideal gas law: R is
universal gas constant
Ideal gas law: T is
absolute temperature
If the oxygen in a full e cylinder is allowed to expand at 1 atm, the volume it would occupy would be?
660L
Water vapor pressure at 37 C =
47mmHg
If you start with a cylinder of 13.8 bar of CO2 in tank and add O2. Final pressure is 138 bar. How much CO2 in percent?
10 %
Equal volumes of gases at the same temperature and pressure contain equal numbers of molecules is what?
Avogadro’s hypothesis
1 mole = ____________ molecules
6.022 x 10^23
1 mole of any gas at STP, occupies ____ liters
22.4L
1 mole at RTP, occupies ___ liter
24.0 liters
1 mole of any gas at BTP, occupies ____ L
25.4 liters
Tare weight of an “E” cylinder is about ____ kg
6
1 mole of N2O is ____ and occupies ___ at ____TP.
____ L per mole
- 44 grams
- 22.4L
- STP
22.4
Alveolar oxygen equation
PaO2 = FiO2 (Pb-Pa(H2O)) - (PaCO2/R)
= 0.21(760mmHg - 47) - (40 / 0.8)
PaO2 approximately
100mmHg
PO2 room air =
99.73 mmHg
PO2 with FiO2 = 0.5 is ___mmHg
300 mmHg
PO2 with FiO2 = 1 is ____mmHg
660 mmHg
If alveolar gases are treated as inert, partial pressure of N2 and O2 is___
760 = PN2 + PH2O + PO2 + PCO2
PN2 + 47 + PO2 + 40
673 = PN2 + PO2
PN2 = 0.79 * 673 = 531
PO2 = 0.21 * 673 = 141.3
The isotherm for nitrous oxide:
If the pressure gets high enough and the temperature gets low enough, it becomes a liquid
The critical temperature of N2O is:
If N2O is above this critical temperature, liquidifaction can not occur.
36.5 C
Since RT (20 C) is below this critical temperature, N2O exists in liquid form
What is the pressure in bar/psi when N2O is at room temperature?
52 bar
764 psi
If N2O is under 750 psi, _____.
Change the cylinder about_____psi.
only gas remains in the cylinder. This is the point when the last drop of the liquid exists, and only the vapor exists.
500
The temperature above which a substance cannot be liquefied however much pressure is applied is called:
critical temperature which is 36.5 C for nitrous.
A sustance above its critical temperature is in its ____ form
gaseous
for example O2 and N2 at room temp
Vapor
A substance in its gas like state but below its critical temperature
For example, N20, CO2, Sevo
When N2O is delivered to the patient at RT, it exists as a _____ but when it reaches BT, it exists as a _____.
- vapor
- gas
- However we will treat N2O as a gas when delivered to the patient
N2O tanks have a ____ ____ so that it does not explode.
fusable plug
When calculating the amount of N2O remaining in the tank, use the ____ _____.
filling ratio
Filling ratio of nitrous (N2O)
Mass of N20/Mass of water that would fill the cylinder (4.8kg) because 4.8L = 4.8 kg
Numerically = Mass of N2O (kg) / volume of cylinder (L)
Filling ratio of N2O is the US is_____
0.68
What are the moles of N2O in E-cylinder?
total grams of N2O in E cylinder (4800 grams)
because 4800 grams N20 = 4800 grams water (4.8 L = 4.8 kg)
(4800gram N2O* 0.68) * 1mole/ 44 gram = 69.5 mole
What is the volume in L of N20 in E cylinder at RT?
69.5 mole N2O * 24L/mole = 1668 L of N2O
If calculating N2O in operating room temp, use ____ not _____ conditions
RT
STP
Temperature is a measurement of the average _________ ________ of the substance being measured.
kinetic energy
