Physics Flashcards
What holds molecules together in a solid
Vanderwaals forces
What is needed for a solid to go to a gas
Enough kinetic energy to break vanderwaals forces
Temperature vs heat (and units of measurement)
Temperature -Numerical ranking of hot or cold -Unit of measurement: Kelvin or Celsius Heat -Energy that is transferred as a result of a temperature difference, flows from hotter to cooler Unit of measurement: Joule
Critical temperature
Temp at which a gas must be at or below to be liquefied by pressure only
- N2O: 97F (liquid at room temp under pressure/cylinder)
- O2: -119C (all gas in cylinder)
Boiling point
Temp when vapor pressure of a liquid = atmospheric pressure
Specific heat
Amount of energy needed to raise the temp of 1kg of a substance by 1 degree C
Conduction
Transfer of heat between objects in direct contact with each other
Convection
Up and down movement of gasses and liquids caused by heat transfer
Radiation
Exchange of heat through electromagnetic waves
Evaporation
Dissipation of heat through skin and respiratory tract
Avagadro’s Law & Number
One mole of gas at standard temperature and pressure (0 C, 1 atm) occupies 22.4L
Number: 6.02 x 10^23
-Number of molecules in 1gm
Dalton’s Law
The total pressure in a mixture of gasses equals the sum of the pressure of each individual gas
Henry’s Law (and practical application)
The amount of gas that dissolves in a liquid is proportional to the partial pressure of the gas in the gas phase
-Helps calculate how much O2/CO2 is dissolved in the blood
Adiabatic explansion (and practical application)
Alteration in the state of gas without exchange of heat (change in temp due to change in pressure, not adding/removing heat or energy)
- When a cylinder of compressed gas is opened to the anesthesia machine (closed space), the pressure and temp in the AM will rise rapidly
- Could cause a fire: no grease/oil allowed on tanks
Woods metal
Soft metal: bismuth, lead, tin, cadmium
- Valve stem safety device, allows cylinder to exhaust instead of explode under excessive heat/pressure
- Melts at 200 degrees
Joule-Thompson Effect
When compressed gas escapes into space, adiabatic cooling occurs due to decrease in pressure
-Opposite of adiabatic expansion
Graham’s Law
Diffusion is directly proportional to molecular weight
Diffusion (what is required for it to happen, CO2/O2 diffusion, determinants of rate of diffusion)
- Diffusion of gas between alveoli and blood requires a different in partial pressure
- CO2 diffuses 20x faster than O2, even though it’s larger it’s more soluble
- Determinant of rate: concentration gradient, electrochemical gradient, lipid solubility, size
Osmosis
Movement of solutes from area of high concentration to area of low concentration through a semipermeable membrane
Fick’s law of diffusion
The diffusion rate of a gas is directly proportional to the partial pressure gradient, membrane area, and solubility of the gas in the membrane
3 Anesthesia occurances that are explained by diffusion
- N2O increases volume (or pressure) of gas occupying spaces in the body
- Second gas effect (N2O is very soluble in the blood, speeds uptake of volatile agent with it)
- Diffusion hypoxia: N2O is so soluble the alveoli fill up with it which dilutes the alveolar O2
Law of Laplace
Cylinder shape: Tension = Pressure x radius
-Applies to heart
Sphere shape: ^ /2
-Applies to normal alveoli and those deficient in surfactant
Surfactant (role, where it’s made)
Decreases surface tension, creates stable alveolar pressures because of increased concentration of surfactant in smaller alveoli (so smaller ones don’t collapse)
-Manufactured by type 2 alveolar cells
Poiseuille’s Law
Flow = (pressure x pie x radius ^4) / (8 x length x viscosity)
Flow is directly proportional to the fourth power of the radius
Resistance to flow equation
Resistance = pressure gradient / flow
-Inversely proportional to r^4
Reynolds number
Predicts when flow through a tube changes from laminar to turbulent
= (velocity x density x diameter) / viscosity
>2000 = turbulent flow, at this point density determines the flow
CO2 absorber equation (sodalime)
CO2 + H2O -> H2CO3
H2CO3 + NaOH -> Na2CO3 + H2O + energy/heat
Na2CO3 + Ca(OH)2 -> CaCO3 + NaOH