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77 Cards in this Set
- Front
- Back
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Force
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that which changes or tends to change the state of rest or motion of an object
measured in newtons (N) will accel. a mass of 1 kg/1m/1sec |
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Force of gravity on a 1 kg mass is ...
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9.81 N
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Velocity
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distance traveled per unit time
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Kinetic energy
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- associates mass and motion (velocity)
- inherent energy in the motion of a body - KE = (mass x velocity)^2 / (2) |
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Pressure
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force exerted by atoms and molecules, generated by kinetic energy, takes into account molec wt and molec motion
Pressure = force/area |
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Density effect
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incr density --> incr pressure
the heavier the substance the more pressure it generates |
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All molecules of a flowing gas or liquid pass through a pathway in the same direction and at the same _____.
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velocity
steady flow! |
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Resistance
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passive force exerted in opposition to another and active force
ex: decline in pressure which results when gas flows through a tube |
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Friction
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resistance to flow in a tube caused by adhesive and cohesive forces
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Viscosity
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measure of a fluids internal resistance to flow
incr w increasing intermolecular forces |
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Change in pressure =
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flow x resistance
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Pascal's Law
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when external pressure is applied to a confined fluid, it is transmitted unchanged to every point within the fluid, not affected by gravity
ex: hydraulic systems |
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Atmospheric pressure
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total force of gas on the earth's surface
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Ambient pressure
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refers to pressure in the environment surrounding an organism (may be atmospheric, below atm, or above atm)
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Torr
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a unit of pressure sufficient to support a 1 mm column of Hg at 0 C
means to quantify pressure, = 1 mmHg |
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What are the units of atmospheric pressure at sealevel?
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760 mmHg =
760 torr = 14.7 psi = 1000 cm H20 = 100 kPa = 1 BAR = 33 ft H20 = 29.92 in Hg |
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Partial pressure
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pressure exerted by a single component gas of a mixture of gases
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What is daltons law of partial pressures
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P1 +P2 + P3... = total pressure
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Critical pressure
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min pressure necessary to liquefy a gas at its critical temp
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Critical temperature
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temp above which a gas cannot be liquefied regardless of how much pressure is applied
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Absolute pressure =
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gauge pressure + atmospheric pressure
0 mmHg gauge = 0 + 760 atm = 760 absolute |
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PSI/PSIA/PSIG
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pounds per square inch
pounds per square inch absolute pounds per square inch gauge |
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aneroid gauge
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without mercury, hollow tube bent and sealed on one end, other end connected to the compressed gas source --> incr in pressure causes tube to straighten and gauge to read higher
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This is a pathway through which a fluid may pass whose length is greater than its diameter
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tube
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Poiseuille's Law
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relates volume of flow through a tube to diameter, pressure differential, length and viscosity
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What law am I?
Volume of flow = (pie x r^4 x change in pressure) / (8 x viscosity x length) |
poiseuilles law
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According to poiseuilles law, diameter and pressure are _____ proportional, length and viscosity are _____ proportional.
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directly, inversely
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Orifice
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opening through which a fluid may pass whose diameter is greater than its length
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This law relates flow through an orifice to density of the gas -- density = mw of the gas, and flow rate of a gas = 1/(sq rt of MW)
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grahams law
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annular flow
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ring-shaped flow
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molecules move through the tube in layers with its greatest velocity at the ____ of the tube.
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center -- this is also called parabolic
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Laminar flow
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molecules move in an orderly fashion parallel to the wall of the tube
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Turbulent flow
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molecules move haphazardly at various angles to the wall of the tube
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Distortions of the pathway can convert laminar flow to _____. When the pathway becomes linear again, the flow becomes _____.
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turbulent, laminar
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_____ is a determinant of gas flow when flow is laminar.
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VISCOSITY
flow = 1/viscosity laminar flow is inversely proportional to viscosity -- much more efficient in relation to delivery of liquids |
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______ is a determinant of gas flow when flow is turbulent.
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DENSITY
Flow = 1/ sq rt of density turbulent flow is inversely proportional to density |
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Viscosity is a measure of the resistance of a fluid to...
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deform under shear stress
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Turbulent flow has some advantages in delivery of _____.
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anesthesia gases
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Critical flow rate
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velocity at which a liquid or gas converts from laminar to turbulent flow, exists for any given fluid at a given tube diameter
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What principle am i?
In a tube of varying diameter, a decr in diameter results in an incr in velocity |
bernoulli's theorem/continuity law
lateral pressure exerted by a fluid passing through a tube of varying diameter is greatest at the widest area where speed is the least |
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According to bernoulli, pressure is least at the ____ portion where _____ is the greatest.
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narrowest, speed
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Venturi effect (Extension of bernoulli)
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generation of subatmospheric pressure after a constriction allows a secong gas to be drawn inward and mixed w the first gas
ex: atomizers, nebs, venturi mask, HFJV |
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Variable orifice flowmeter
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- tapered tube w variable surface area
- narrow at bottom, wide at top - thorpe tube - no change in pressure w incr in flow |
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This is the temp at which vapor pressure of a liquid equals ambient pressure
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boiling point -- incr ambient pressure yields incr boiling point
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Which IA boils at room temp?
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desflurane! 22.8 C
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This is the temp at which, if a volume of air is cooled, moisture precipitates out -- can never be greater than air temp
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dew point
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This is the conversion of a volatile liquid to a gas/vapor, process by which particles escape the surface of a liquid, endothermic process, rate determined by temp of liquid
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vaporization
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Vaporization will eventually cease due to cooling unless..
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heat is applied to the system
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Temperature and vaporization are ______ proportional.
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directly
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Efficiency of clinical vaporization can be increased by...
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increasing the surface area of the interface between the liquid and the gas
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Back pressure
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uneven delivery of vapor as a result of cahnges in vaporization due to pressure changes in the system during respiration (solution is baffles)
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This is the pressure exerted by vapor particles in equilibrium with a liquid.
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vapor pressure
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What does vapor pressure depend on?
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- polarity (incr polarity will decr VP)
- mass (incr pass decr VP) - temp (incr temp incr VP) |
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When does equilibration of vaporization occur?
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when as many molecules return to the liquid as escape from it -- atmosphere above the liquid said to be saturaed
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This is the amt of heat absorbed to convert a liquid to a gas at its boiling point.
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latent heat of vaporization
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What is the vapor pressure of water at room temp, body temp, and boiling point?
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20 C - 17.5 mmHg
37 C - 47 mmHg 100 C - 760 mmHg |
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What are the vapor pressures of halothane, isoflurane, desflurane, and sevoflurane?
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halo- 244
iso- 240 des- 669 sevo- 160 |
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This is a form of energy that can be transferred from a hotter substance to a cooler substance -- in the form of kinetic energy which resides in the molecules of a substance.
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heat!
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heat energy flows from an area of _____ to an area of ____.
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high heat to low heat -- heat exchange!
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Thermal conductivity
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measureent of a substances ability to conduct/exchange heat
copper/bronze vaporizer housings have incr thermal conductivity! |
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This is the thermal state of a substance which determines whether it will give heat to another substance or receive heat from another substance -- avg kinetic energy of the molecules of a substance.
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temperature!
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STP
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0 deg C, 273 K
760 mmHg 1 atm 22.4 L 6 x 10^23 molecules |
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This is the scale in which there are 180 degrees between the freezing point of water (32) and the boiling point (212)
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fahrenheit
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This is the scale in which there are 100 degrees between th freezing point of H20 (0) and the boiling point (100).
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celsius
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This is the scale in which there are 100 degrees between the freezing point of h2o (273) and the boiling point (373) -- measured in degrees from absolute zero
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kelvin
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Triple point of water
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temp and pressure at which water vapor, liquid and solid phases are in equilibrium
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Temp conversions
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C = (F-32) x 0.56
F = (C x 1.8) +32 K = C + 273 |
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calorie
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unit of heat measurement, amt of heat required to raise temp of 1 g of h20 1 deg C
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This is the quantity of heat which is liberated per gram molecule of a substance when it undergoes complete combustion.
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heat of combustion
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This is a change of state of matter requiring the input of heat energy, energy flows into the system
ICE to WATER to VAPOR |
endothermic
(vaporization) |
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This is a change of state of matter requiring the output of heat energy, and energy flows out of the system
VAPOR to WATER to ICE |
exothermic
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4 types of heat loss
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conduction
convection (30%) radiation (40%) evaporation |
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This is heat transferred from one point to another by direct contact
ex: pt in contact w a cold surface |
conduction
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This is heat loss where heat is transferred when a fluid flows over a solid while temp between the fluid and solid are different
ex: air flowing over pts body |
convection
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This is the transfer of heat through divergence in all directions from a center
ex: body heat moving toward other objects in a room |
radiation
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This is the transfer of heat through converting a liquid to a vapor, endothermic process
ex: humidification of dry inspired gas |
evaporation
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This is the heat produced in the body by exposure to and absorption of waves that are not in themselves hot.
ex: UV light, microwaves |
conversion heat
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