Physics & Gases Flashcards
Kinetic energy
The energy that an object possesses when it is in motion
Potential energy
Stored energy
States of matter
Solid
Liquid
Gas
Kinetic energy of solids
Very little, strong bonds, incompressible
Kinetic energy in liquids
Some activity, cohesive forces not as strong
Kinetic energy in gas
Greatest amount of energy, highly compressible, weakest bonds
Kelvin to Celsius
K=C+273
Melting point
Temperature at which solid converts to liquid
Freezing point
Temperature at which liquid changes to solid
Boiling point
Temperature at which liquid converts to gas
Latent heat
The amount of heat that must be added to a substance to cause a complete change of state
Sublimation
Molecules can completely bypass the liquid state and chage directly to gas
Evaporation
Occurs when some of the liquid molecules gain enough energy to break through the surface and become gaseous
Critical temperature
The temperature above which gaseous molecules cannot be converted back to liquid no matter the pressure exerted on them
Critical pressure
Pressure that must be applied to the substance at critical temperature to maintain equilibrium between liquid and gas phases
Types of pressure
Cwp, psi, mmHg, kPa, torr
Atmospheric pressure
The pressure that atmospheric gases exert on objects within the earths atmosphere
Sea level 760mmHg
Pressure equivalents
760 mmHg
1034 cwp
14.7 psi
1 ATM
Cwp/mmHg conversion
Cwp X .735=mmHg
Cwp/70.34=psi
1.36 X mmHg = cwp
Composition of air
Nitrogen 78%
Oxygen 20.9%
CO2 0.03%
Trace gases .9%
Viscosity
Force opposing the flow of fluid or gas
Factors affecting viscosity
Cohesive forces and kinetic activity
Increased temp of liquid will DECREASE viscosity
Increased temp of gas will INCREASE viscosity
Surface tension
Cohesive forces between liquid molecules at a gas-liquid interface
Boyles law
The volume that gas occupies when it is maintained at a constant TEMPERATURE is inversely proportional to the absolute pressure
V1P1=V2P2
Charles law
The volume of gas at a constant pressure increases proportionally with increased temp
Temp in Kelvin
V1/T1=V2/T2
Gay-Lussac’s law
Volume of gas is held constant the gas pressure rises as the absolute temp rises
p1/t1=p2/t2
Combined gas law
Absolute pressure of a gas is inversely related to the volume it occupies and directly to its Absolute temperature
P1v1/t1=p2v2/t2
Dalton’s law of partial pressure
The absolute pressure of a gas mixture equals the total pressure of the system
Avogadro’s law
Equal volumes of gas at the same pressure And temperature contain the same number of molecules
1 mole is 6.02X10^23
Diffusion
Movement of molecules from high concentration to low concentration
Graham’s las
Rate of diffusion is inversely proportional to the square root of the mass or density
Lower density, more diffusible gas
Henry’s law
The higher the partial pressure of a gas the more it will dissolve
Ficks law
Diffusion across a semipermeable membrane
- directly proportional to surface area, partial pressure gradient, solubility
- indirectly proportional to GMW, thickness of membrane
Laminar flow
Streamlined, small airways of lungs
Turbulent
Chaotic, large airways
Transitional flow
Mixture of laminar and turbulent flow
Occurs where tubes divide
Poiseuille law
•Under conditions of laminar flow, the difference in pressure required to produce a given flow is defined by Poiseuille’s law.
Reynolds number
Describes how other factors can produce turbulent flow
Faster flow is more turbulent
Bernoulli principle
As the forward velocity of a gas increases its lateral pressure decreases and its forward pressure increases
Smaller jet more entrainment
Venturi principle
The pressure drop that occurs distal to a constriction in a tube can be restored to the ore constriction pressure if there is a dilation in a tube distal to the constriction
Coanda effect
If the wall does not have a side port for entraining another fluid, the low pressure adjacent to the wall draws the stream of fluid against the wall
Air composition
Colorless, odorless Composed of N, O, CO2, and trace gases Nonflammable, supports combustion Gas or liquid Prepared synthetically and shipped in gas cylinders
Oxygen
Colorless, odorless, tasteless 20.9% of earths atmosphere Nonflammable,supports combustion Oil and grease are explosive near O2 Gas at room temp, prepared by fractional distillation Liquid at <-184C
Carbon dioxide
Colorless, odorless
Nonflammable, does not support combustion
Solid -56C, liquid below 31.1C, gas above 31.1C
Byproduct from ammonia, lime and kilns, combustion of coal and natural gas or fractional distillation
Helium
Colorless, odorless, tasteless Prepared from natural gas or uranium ore Inert gas Nonflammable, does not support combustion Does not support life
Nitric oxide
Colorless Nonflammable, supports combustion NO + air = nitrogen dioxide Can be potent irritant to the lungs NO in low doses is strong vasodilator (premie PPH)
Nitrous oxide
N2O, laughing gas
CNS depressant (anesthetic)
Use caution with COPD & asthmatic
Liquid oxygen
Less expensive
Gaseous oxygen occupies a volume 860 X liquid O2
Continuous supply system
Primary- large liquid system, refilled at reg intervals
Reserve- small liquid system or bank of cylinders, contains avg day supply
Alternating supply system
Two banks of cylinders when primary empties, secondary becomes primary
Piping systems
Seamless, type K or L, copper or standard wt brass, labels every 20 ft
Zone valves
Isolate areas of hospital, O2 air and vacuum
- mainline entering hospital, each riser, between each zone And mainline, critical care areas and surgical suites
O2 concentrator
Produce enriched oxygen from ATM air Semipermeable - air diffused Molecular sieve- N2 removed by pellets Less than 6lpm 92-97% 10lpm 50%
