Physical Principals of Respiratory Care Flashcards

Question

Specific Gravity

Answer 1

Specific gravity is the ratio of density of one fluid compared to the density of a reference substance Specific Gravity is a relative term When looking at a gas’s specific gravity it will be relative to air at 1.28 g/L Specific gravity is a unit less number The normal SG of urine is ~1.001 to 1.035

Answer 2

Gas Specific Gravity=Density (g/L) / 1.28 g/L

Answer 3

When looking at a liquid’s specific gravity it will be relative to water at Liquid Specific Gravity=Density (g/L) / 1000 g/L or 1000 kg/m3

Answer 4

When two or more chemical substances react, one or more substances different from the original will form A + B ⇔ C + D As the arrow suggests the reaction is completely reversible There is a definite relationship that exists between the speed and rate of the reaction and the quantity or concentration of the products Other factors that will also play a role includes the chemical nature of the substance, the presence of a catalyst, and temperature The rate of reaction is directly proportional to the concentration of the reactants.

Answer 5

A practical example in the body of the Law of Mass Action is the Hydrolysis Equation H2O + CO2 ↔ H2CO3 ↔ H+ + HCO3- This equation will reach equilibrium at some point Not all the content of any part will disassociate fully. It is completely reversible. The equilibrium can be shifted in either direction with the addition of parts.

Answer 6

Adding CO2 to the equation pushes it to the right. This will increase [H+] and therefore ↓ pH. This can occur from the following Ex. Hypoventilation, COPD, renal failure, fever, etc.

Answer 7

Adding bi-carb will push the equation to the left nullifying [H+] and increasing pH and eventually increasing CO2as well. This can occur from the following Ex. Kidneys retaining bicarbonate due to chronic condition, certain acute conditions that result in the use of the bicarbonate drip (need to make sure there is adequate ventilation provided in this case

Answer 8

Weak attractive forces which results in a lack of restriction in their movement There is a rapid random motion meaning their will be frequent collisions Gas is a fluid meaning they have the ability to flow Gases are very easy to compress and expand Gases have the greatest amount of kinetic energy and the least amount of potential energy Gases exist at temperatures above the substance’s critical temperature

Answer 9

* A vapour is the gaseous form a substance that is below its boiling point and/or critical temperature * Ex. Water vapor in the lungs, clouds * Most gases that we use as RTs will be above their boiling points * Above the boiling point, pressure will have to be added to return the gas to its liquid form until the critical temperature is reached * Ex. CO2and N2O

Answer 10

A vapor will exert gas pressure just the same as a true gas Vapor pressure will increase with temperature A decreased temperature is known as a dew point Head pressure is the pressure on the surface of a liquid

Answer 11

The force the molecules exert as the hit the surface of a liquid and escape into the gaseous phase When vapor pressure is equal to atmospheric pressure their will be rapid boiling This is very powerful and can be explosive

Answer 12

Solids will maintain their shape due to their strong attractive forces this means that they are not easy to compress These forces are known as Van der Waal forces Solids have the greatest amount of potential energy and the least amount of kinetic energy The molecules in solids have the shortest distance to travel unil they collide with one another

Answer 13

Still have strong attractive forces that create a fixed volume but molecules are able to move more feely than solids which is why they take the shape of their containers They have the ability to flow which I s why they are considered to be fluids Like solids, they are still quite dense and not easy to be compressed

Answer 14

The physical state of any substance is determined through its relation to kinetic energy and potential energy Exothermic Reaction-Releases energy Endothermic Reaction-Absorbs Energy At the melting point of ice will begin to change into it’s liquid form A full change into liquid for requires additional heat, this additional heat will change the state of water but not an immediate change in temperature This extra heat that is needed is known as the latent heat of fusion

Answer 15

**Boiling:** For each substance there is a temperature at which the substance will change from a liquid to a gas The boiling point of a liquid is the temperature at which vapor pressure will equal/exceed the atmospheric pressure. When atmospheric pressure is low liquid molecules will escape more easily and boiling will occur at a lower temperature . This means that the boiling point of a gas will decrease with an increased elevation

Answer 16

Condensation is the reverse of boiling Condensation is giving heat back into the surrondings

Answer 17

Vaporization: heat comes from the surroundings

Answer 18

Evaporization is a form of vaporization where heat is taken from the air surrounding the liquid and cooling the air When water (or other substances) undergo a phase change from a liquid to a gas bellows its boiling point it is called evaporation. This will occur when we add enough kinetic energy. The rate of evaporation will increase when there is a increase in temperature, surface area, or a decrease in pressure

Answer 19

The energy that is required to vaporize a liquid is known as the latent heat of vaporization This is the number of calories that are required to vaporize 1g of a liquid at its normal boiling point

Answer 20

When a solid changes directly to a gas it is called sublimation

Answer 21

Both evaporation and condensation is very important in regards to breathing, as there is a delicate balance between evaporation and condensation that is needed so that the airway does not dry out and become irritated. Mechanical ventilation will bypass the normal body processes that add heat and humidity into inspired air, which will compromise the balance between condensation and evaporation

Answer 22

The highest temperature at which a substance can exist as a liquid when under a specific pressure Above this temperature the kinetic activity will be so great that the attractive forces of the substance are not enough to keep it a liquid A true gas such as O2will have a critical temperature that is so low it can be store in room temperature without turning in to a liquid. In contrast a vapor is the gaseous state of a substance coexisting with its liquid or solid state at room temperature and pressure This is why molecular water is referred to as water vapor A gas can be liquefied by being cooled to below it’s boiling point or by being cooling to less than its critical temperature and being compressed The more a gas is cooled below its critical temperature the less pressure that is needed to liquify it However under no circumstances can pressure alone liquify a gas that exists above its critical temperature Any gas with a critical temperature above ambient should be able to be liquefy simply by having pressure applied Both CO2 and N2O have critical temperatures above normal room temperature This means that both gases can be store as liquids when under pressure, usually strong metal containers

Answer 23

The pressure that is needed to maintain equilibrium between the liquid and gas phase of a substance It is the force required to change a gas to a liquid when as critical temperature

Answer 24

Together the critical pressure and critical temperature represents the critical point of a substance

Answer 25

The set of circumstances needed to allow a substance to exist simultaneously as a solid, liquid, and gas This happened with water at about 0.0006 atm and near 0 degrees Celsius

Answer 26

Flowmeter is a pressure gauge calibrated in Lpm UNCOMPENSATED FOR BACK PRESSURE-Meaning that when there there is back pressure the guage will read higher than what the patient is receiving As pressure enters there will be a tube that straightens out indicating the pressure Not position dependant Obstruction to flow will result in back pressure