NOTES FOR UNIT 2, GAS LAWS

1. = Ideal Gas Law- applies to gases above boiling point

&= nbsp; &nbs= p; PV =3D nRT (doo-dah)

2. Boyle’s La= w- if temperature and mass remain constant, volume of gas varies INVERSELY with pressure. &nbs= p; P₁V₁ =3D P₂V₂

3. Charles’ L= aw- if pressure and mass remain constant, volume of gas varies DIRECTLY with temperature. &= nbsp; V₁/T₁ =3D V₂/T₂

4. Gay-Lussac’= ;s Law- if volume and mass remain constant, pressure varies DIRECTLY with temperature. &= nbsp; P₁/T₁ =3D P₂/T₂

5. BTPS- body temperature and pressure, saturated (inside lungs)

ATPS- ambient temperature and pressure, saturated

&= nbsp; STPD- standard temperature 0^oC, standard pressure 760 mm Hg, dry<= /o:p>

6. = water vapor exerts 47 mm Hg at 37^o C

7. = Volume conversion: &n= bsp; V_{2
=3D V₁ x P₁ x T₂}<= /p>

&= nbsp; &nbs= p; &= nbsp; &nbs= p; &= nbsp; P2 x T₁

&= nbsp; Remember to correct for water vapor and use Kelvin temperatures

8. = Dalton’s La= w of Partial Pressures

&= nbsp; &nbs= p; 1) total pressure of a gas mixture is equal to sum = of all partial pressures of constituent gases.

&= nbsp; &nbs= p; 2) partial pressure of each gas in the mixture is t= he pressure it would exert if alone.

3) the partial pressu= re exerted by each constituent gas is proportional to the percentage of that g= as in the mixture.

9 & 10. = ; Major component gases in the atmosphere:

&= nbsp; &nbs= p; Nitrogen (N₂) &nbs= p; &= nbsp; 78.08%

&= nbsp; &nbs= p; Oxygen (O₂) &nbs= p; &= nbsp; 20.95%

&= nbsp; &nbs= p; Argon (Ar) &nb= sp; = 0.93%

&= nbsp; &nbs= p; Carbon Dioxide (CO₂) &= nbsp; 0.03%

&nb= sp; = Trace elements = ; &n= bsp; 0.01%

11. Parti= al pressure of gas =3D percentage of gas x (barometric pressure minus water va= por pressure)

12. diffusion- intermolecular mingling that occurs as a result of molecules randomly bouncing off each ot= her, producing a homogenous mixture

13. Graham’s Law- rate of diffusion of a gas into a liquid is inversely proportional to the square ro= ot of the density of the gas, i.e., dense gases diffuse slower

14. Henry’s Law- amount of= gas dissolving in a liquid at a given temperature is proportional to the partial pressure of that gas. i.e., higher partial pressure, more gas dissolved into liquid

15. more dense gases will diffuse slower=

&= nbsp; higher the pressure gradient or partial pressure, the = faster the diffusion

16. Even though oxygen is less dense, carbon dioxide has a much higher solubility coef= ficient, the end result is that CO₂ diffuses 19 x’s faster than O2.

17. Flow- movement of a gas volu= me from one place to another in relation to time. Unit is usually liters/minute.

18. Flow can be increased by 1) increasing the pressure gradient or 2) increasing the size of the opening/d= ecreasing the resistance to flow.

19. Bernoulli principle- as the forward velocity of a gas increases, its lateral pressure decreases with corresponding increase in forward pressure.

20. = Jet entrainment system: affected by:

1) jet orifice size, smaller the jet orifice size, more entrainment, more total flow, lower the oxygen %.

2) entrainment port s= ize, larger the entrainment port size, more entrainment, more total flow, lower = the oxygen %.

21. Venturi principle: by adding= a tube, after the jet, which gradually increases in diameter (funnel), and angulation is not > 15^o, the lateral pressure will be restore= d to its pre jet level.

22. Effects of back pressure and obstruction on an air entrainment system.

1) downstream obstruc= tion in an air entrainment system will create back pressure on device and decrea= se entrainment, decrease total flow and increase oxygen percentage<= /span>

23. If entrainment ports are blocked, entrainment decreases, total flow decreases and oxygen percentage delivered by device increases

24. Poisueille’s Law: the amount of pressure needed= to drive a gas (airways resistance) will increase if:

&= nbsp; &nbs= p; length of the tube increases

&= nbsp; &nbs= p; viscosity of the gas increases

&= nbsp; &nbs= p; flow of the gas increases

&= nbsp; &nbs= p; radius of the tube decreases

25. Accor= ding to the Reynold’s equation, gas flow is more likely to be turbulent if= :

&= nbsp; &nbs= p; density of the gas is increased

&= nbsp; &nbs= p; flow of the gas is increased

&= nbsp; &nbs= p; diameter of the tube is increased

&= nbsp; &nbs= p; viscosity of the gas is decreased

26. Turbu= lent flow begins when the Reynold’s number is greater than 2000.

27. Coanda effect- result of Bernoulli principle. Basis for fluidic devices in ventilators. Because of the lateral wall pressu= re decrease, gas flow will adhere to the wall of the tube.

9/2011