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Flashcards in Physics and Chemistry Deck (49)
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1

The closer the vapor pressure is to atmospheric pressure, the more easily it _____.

boils
*this is why desflurane is placed in a heated vaporizer

2

Vapor pressure is a function of _______.

temperature

3

The % concentration of any gas is found by _______.

dividing the pressure of the gas over the total pressure. (760 for 1 atm)

4

If halothane was added to an isoflurane vaporizer, what would happen to the delivered concentration? halothane added to sevo?

added to iso: it would be about the same because the VP of halothane is 244 and Iso is 240mmHg

added to sevo: the delivered concentration would be more than what was dialed because the VP of halothane is 244mmHg versus Sevo VP of 170mmHg

5

To remember what happens to a volatile agent that was added to the wrong vaporizer, just remember:
HLH
LHL

HLH= if a HIGHER VP agent is placed in a LOWER VP vaporizer, the concentration will be HIGHER

LHL= if a LOWER VP agent is placed in a HIGHER VP vaporizer, the concentration will be LOWER

6

Desflurane vaporizer is heated to _____. What is the vapor pressure at this temperature?

39 degrees C; approximately 2 atm or 1500mmHg

7

Name some units of pressure.

mmHg, cm H2O, atm, psi, kPa, bar

8

What is the conversions for the following:
mmHg--> cm H2O
atm--> mmHg--> psi--> kPa--> bar
psi--> mmHg

1 mmHg= 1.36 cmH2O
1 atm=760 mmHg=14.7 psi=101 kPa= 1 bar
1 psi= 54 mmHg

9

What type of gauges measure high pressures?

Bourdon gauge
measures the pressure relative to atmospheric pressure, not the absolute pressure--> when it reads 0... the pressure inside is equal to the atmosphere

10

Define tension.

"force" along a straight line

11

T= P x r is what law?

Law of LaPlace
as a structure expands (ie: radius increases-->cylindrical-- blood vessel), the tension (force) in the wall of the structure increases

12

In regards to the Law of LaPlace.... If you have a small soap bubble on one end of a straw and a large one on the other end, what will happen?

The small one will collapse because it has a greater pressure
*this is ONLY true when there is a liquid-air interface..... this happens in ARDS, when smaller alveoli collapse due to lower than normal surfactant and empty into alveoli with lower pressures--> causing atelectasis
** normal alveoli with normal surfactant--> tension would increase with the radius

13

According to Poiseuille's Law, doubling the radius increases flow _____ times.

16 times
tripling the radius= increases flow 81 times
halving the radius= decreases flow to 1/16th of original

14

Changing what single factor, according to Poiseuille's Law, has the most impact on flow?

the radius

15

What property of a fluid determines flow, when flow is laminar?

viscosity

16

When does flow become turbulent?

If:
1) velocity of flow is high
2) tube wall is rough (corrugated)
3) kinks, bends, narrowing, or branches (RAE tube)
4) fluid flows through an orifice
*does not become turbulent when flowing through an angled tube if the angle is <25 degrees
5) reynolds # exceeds 1500-2000

17

Resistance to flow ______ when flow becomes turbulent.

increases

18

What explains why the temperature of a cylinder of compressed gas decreases as the gas is released?

Joule-Thompson effect

19

How to remember the common gas laws???

Can the gay people possible b---- v-----.

20

What is the generalized ideal (universal) gas law?

PV=nRT
where P= pressure, V=volume, T=temperature, n=moles of gas, and R=universal gas constant

21

One ____ is the molecular weight of a substance in grams.

mole

22

_______ described the relationship between the amount of gas and volume of gas.

Avogadro

23

What is Avogadro's number?

the number of molecules in one mole of a substance is 6.022 x 10 to the 23rd

24

What was Avogadro's hypothesis?

one mole of gas at standard temperature (0C) and standard pressure (1atm) occupies a volume of 22.4 liters

25

2 moles of gaseous N2O occupy what volume under standard conditions?

22.4 x 2= 44.8 liters

26

What is critical temperature?

gases liquefy if sufficient pressure is applied and the temperature is below a critical value called the critical temperature
ex) critical temperature of N2O is 36.5C, so it can be compressed and stored as a liquid at room temperature
ex) critical temperature of O2 is -119C, O2 cannot be liquefied at room temperature no matter how much pressure is applied

27

Adiabatic means______.

heat cannot be dissipated ("constant heat")

28

What is the Joule-Thompson effect?

"Joule is Cool"
when compressed gas is allowed to escape freely into space, the process is adiabatic and cooling occurs (explains why condensation forms after opening a valve)

29

At 20C, a full E-cylinder of O2 has a pressure of ~ _______psi and contains approximately ______L.

1900-2200psi; 660L

30

What law is all about diffusion?

Ficks