Intro to Respiratory Care - Unit II Lecture Notes

Flashcards covering energy, states of matter, gas laws, and respiratory care physics based on the Unit II lecture notes.

Potential Energy

The energy of position or stored energy, which is the result of strong attractive forces between molecules and is not relative to the environment.

Kinetic Energy

The energy of motion relative to the environment and other moving or stationary objects, determined by speed/velocity and mass.

Solids

A state of matter that maintains a fixed shape and volume with strong mutual attractive forces and very low kinetic energy.

Liquids

A state of matter where molecules have less mutual attractive forces than solids, can move more freely, take the shape of their container, and cannot be easily compressed.

Viscosity

The thickness of a liquid or its opposition to flow.

Cohesiveness

The property of liquid molecules to be unified and stick together as one body.

Density

A ratio of a substance’s mass to volume; for a gas, it is calculated as molecular weight divided by the universal molar volume of $22.4\,L$.

Gasses

A state of matter with weak attractive forces and high kinetic energy exhibiting rapid, random motion and no fixed volume or shape.

Velocity

How fast something moves in a particular direction.

Kinetic Molecular Theory

A theory applying to gases stating that no energy is lost during collisions, molecular volume is negligible, and there are no forces of mutual attraction between molecules.

Brownian motion

The random motion of smaller particles (suspended matter $<3\,\mu m$) that deposit in the respiratory region of the lung where bulk gas flow ceases.

Absolute Zero

The temperature at which all molecular activity ceases and there is no kinetic energy, defined as $-273^\circ C$, $0^\circ K$, or $-460^\circ F$.

Critical Temperature

The highest temperature at which a substance can exist as a liquid; for water, this is $374^\circ C$.

Critical Pressure

The lowest pressure necessary at the critical temperature of a substance to maintain it in a liquid state.

Critical Point

The highest temperature and lowest pressure required to maintain equilibrium between liquid and gas forms.

Atmospheric Pressure

The force exerted on a surface by the air above it as gravity pulls it to the earth, equivalent to $760\,mm\,Hg$ or $14.7\,PSI$ at sea level.

Tension

A term referring to pressure when a gas is dissolved in a liquid such as blood or fluid.

Dalton’s Law (Partial Pressure)

States that the total pressure of a mixture of gases must equal the sum of the partial pressures of all component gases.

Torr

A unit of pressure equivalent to $1\,mm\,Hg$, named after the inventor of the mercury barometer.

Avogadro’s Law

States that equal volumes of gases at the same temperature and pressure must contain the same number of molecules ($6.023 \times 10^{23}$).

Avogadro’s constant

The number of atoms, molecules, or ions in one mole of a substance, equal to $6.023 \times 10^{23}$.

Molar Volume

The ideal volume of one mole of any gas at STPD (Standard Temperature Pressure Dry), which is $22.4\,L$.

Diffusion

The process whereby molecules move from an area of higher concentration to areas of lower concentration.

Graham’s Law (Gas Diffusion)

States that the rate of diffusion of a gas is inversely proportional to the square root of its gram molecular weight ($D_{gas} = 1 \div \sqrt{gmw}$).

Fick’s first law of diffusion

States that the rate of diffusion of a gas into another gas is proportional to its concentration and the bulk movement through a biologic membrane.

Henry’s Law

Predicts how much of a gas will dissolve in a liquid at a given temperature, where volume ($V$) equals the solubility coefficient ($\alpha$) times the partial pressure ($P_{GAS}$).

Solubility Coefficient

The volume of a gas that will dissolve in $1\,ml$ of a given liquid at standard pressure and specified temperature.

Boyle’s Law

States that at a constant temperature, the volume of a gas varies inversely with the pressure exerted on it.

Charles’ Law

States that if pressure and mass remain constant, the volume of a gas varies directly with the absolute temperature.

Gay-Lussac’s Law

States that if volume and mass remain constant, the pressure of a gas varies directly with the absolute temperature.

Combined Gas Law

A law that combines the relationships between pressure, volume, and temperature.

Ideal Gas Law

A law that accounts for pressure, volume, temperature, and density to describe gas behavior.