Lecture 4 Formulas

Question 1

Boyle’s Law

Answer 1

At constant temperature, volume of a gas varies inversely with absolute pressure
T=PV
Derived from PV=nRT
P1V1=P2V2

Question 2

Charles’ (Gay Lussac’s) Law

Answer 2

At constant pressure, the volume of a gas varies directly with absolute temperature
nR/P=V/T
V1/T1 = V2/T2

Question 3

The Third Law

Answer 3

At constant volume, the absolute pressure of a gas varies directly with the absolute temperature
nR/V = P/T
P1/T1 = P2/T2

Question 4

Standard Temperature and Pressure

Answer 4

STP
T = 273K or 0C
P = 760 mmHg

Question 5

Room Temperature and Pressure

Answer 5

T = 293K or 20C
P = 760 mmHg

Question 6

Body Temperature and Pressure

Answer 6

310K or 37C

P = 760 mmHg

Question 7

Dalton’s Law of Partial Pressures

Answer 7

In a mixture of gases, the pressure exerted by each gas is the same as that which it would exert if it occupied its own container.
Vx/Vy = Px/Py

Question 8

Avogadro’s Hypothesis

Answer 8

Equal volumes of gases at the same temperature and pressure contain equal numbers of molecules.
At STP - 1 mole of gas occupies 22.4L
At RTP - 1 mole of gas occupies 24.0L
At BTP - 1 mole of gas occupies 25.4L
Avogadro's Number 6.022x10^23

Question 9

E Cylinder

Answer 9

E cylinder tare weight is approximately 6kg

Volume = 4.5 L

Question 10

Alveolar Oxygen Equation

Answer 10

PAO2 = FiO2 (PB-PAH2O) - (PACO2/R)
PAO2 - partial pressure of oxygen in the alveoli
FiO2 - fraction of oxygen
PB - barometric pressure
R = Respiratory quotient (carbs = 1, proteins = 0.8, fats = 0.7, average = 0.8)
PAH2O is pressure water = 47 mmHg

Question 11

Alveolar Oxygen

Answer 11

At room air PAO2 = 100 mmHg
At 50% O2 PAO2 = 300 mmHg
At 100% O2 PAO2 = 660 mmHg

Question 12

Gas vs Vapor

Answer 12

Gas is a substance that is above its critical temperature at room temperature (O2 and N2)
Vapor is a gas substance that is below its critical temperature. (N2O,CO2, Sevo)
Critical Temperature N2O=36.5
Critical Temperature O2 = -119C

Question 13

Filling ratio

Answer 13

US = 0.68
UK = 0.65 or 0.75
Mass of N2O/Mass of Water to Fill Cylinder

Question 14

Ideal Gas Constant

Answer 14

8.31 J/mol K

62 mmHg L /mol K

Question 15

Water Vapor Pressure

Answer 15

Water at 37C is 47mmHg

6.3kPa