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Physics & Chem
SIUE-Nicole's Physics for the Final Exam
Question | Answer |
---|---|
What is a mole? | The gram molecular weight of a substance. Ex. 1 Dozen eggs, or a dozen feathers-not the same wt. but the same quantity. One mole of NH3 has 6.022x10^23. One mole of Cu has 6.022x10^23 as well, physical quantity. |
Mole (numerical value)- Avogadro's Number | 6.022x10^23. Defined as the number of atoms in 12 grams of carbon -12. |
Avogadro's Law | The hypothesis is that one mole of a gas at standard temperature 0 Celsius and standard pressure 1 atm occupies a volume of 22.4L; Avogardo's # is 6.02x10^23 & is the number of particles in one mole of a substance. ex: a half mole=11.2L and 2 moles=44.8L |
Fick's Law of diffusion (definition). | Law of the diffusion of a gas across a fluid membrane. |
Fick's Law (equation) | Rate of diffusion= KA(P2-P1)/D |
Fick's Law (equation)- what does K and A stand for? | Constant for a given gas at a given temp (k), proportional to the surface area over which diffusion is taking place (A). |
Fick's Law (equation)- what does the P2-P1 and D stand for? | Proportional to the difference in partial pressures of the gas across the membrane, (P2-P1), Inversely proportional to the distance over which diffusion must take place (thickness of the membrane)-(D)-have a thin membrane=fast, thick=slow. |
Graham's Law definition (Using Kinetic Engery) | Average kinetic energy of the molecules of two samples of different gasses at the same temperature is identical. |
Graham's Law (equation) | KE=1/2*mv^2-> KE=kinetic energy, m=mass of the particle, v=average velocity of the particles. |
Graham's Law (With Molar Mass) | The rate of effusion of a gas is inversely prop to the sq. root of the mass of its particles. In a concentration of mixed gases, the gas with the largest molar mass will take longer to diffuse across the same membrane. |
Graham's Law (With Molar Mass)-Equation | Rate 1/Rate 2 = square root--> (M2/M1) |
The ideal gas law (definition) | An equation of state of an ideal gas. Combines the three primitive gas laws. Roughly accurate for gases-becomes increasingly inaccurate at higher pressures and lower temperatures. |
Based on the theory that the gas molecules do not interact with any repulsive of attractant forces? | The ideal gas law-was based on the different characteristics of gas compared to liquid. The same forces exist, but the molecules are spread further apart so it isn't apparent. |
Ideal gas law (equation) | PV=nRT P=pressure, V=volume, T=temperature, R=molar gas constant, n=number of moles |
The volume and pressure of an ideal gas held at a constant temperature. TEMPERATURE REMAINS CONSTANT-VOLUME & PRESSURE REACT- INVERSE RELATIONSHIP. as one increases the other decreases. | Boyle's Law PV=k or P1V1/P2V2 ex:compressed air in a cylinder, Ambu bag. (think- the temperature is constant when boiling) |
Charles Law (think Prince Charles has pressure on him constantly) | Pressure is constant. Temperature and volume changes. T/V=k or T1/V1=T2/V2 or T2/T1=V1/V2 |
Gay- Lussac's Law (think gay likes volume where most don't) | Volume remains constant, temperature and pressure change. Linearly ratio, directly proportional. Temp increases, pressure increases. |
Dalton's Law | The total pressure of a mixture of gasses is equal to the sum of the partial pressures. Calculation of PP of a gas by multiplying % concentration by total pressure, calculation of % concentration by dividing PP of gas by the total pressure. |
The mass of a gas that dissolves in a definite volume of liquid is directly proportional to the pressure of the gas. | Henry's Law P=kC P=pressure, C=concentration, k=Henry's law constant. |
Henry's Law (explain) | Twice as much O2 will dissolve in arterial blood if the alveolar PP of O2 is doubled.Solubility of a gas in liquid is directly proportional to the PP of the gas overylying the liquid. Diff gasses have diff solubilities & this also affects the rate. |
Law of LaPlace (definition) | Increased pressure difference=increased wall tension. Thicker the wall=less tension. Larger radius=more tension. Dilated cardiomyopathy:distended ventricular wall (radius increases) |
Law of LaPlace (equation) | T = (P*R)/M T=tension, P=is the pressure difference across the wall, R=is the radius of the cylinder, M=is the thickness of the wall |
What Law explains the tension in the wall of a blood vessel is proportional to the radius. A blood vessel with an aneurysm has greater wall tension. Greater ventricular filling during diastole produces greater wall tension end-diastole. | Law of LaPlace |
Principle of stretch in the ventricle creating a maximal contraction of the heart muscle and chamber is explained by what law? | Starling's Law- The greater the tension in the ventricular wall at end-diastole, the greater the stroke volume. |
Pouiseulle's Law (definition) | Explains how pressure, tube radius, tube length and fluid viscosity contribute to laminar flow. |
In IV's the flow is increased with a decreased gauge or increased diameter catheter or needle, and by decreasing the length of the needle, and raising the IV bag is explained using who's law? | Pouiseulle's Law |
Pouiseulle's Law (equation) | pie=n n(pressure difference)(radius)^4/8(viscosity)(length) Changing the radius produces the greatest effect. |
Allows calculation of resistance,R, of flow through a tube | Ohm's Law R=(P in-P out) Allows calculation of SVR, 80 x (MAP-CVP)/CO |
Venturi Effect | When fluid flows through a constricted region of a tube (venturi tube) the velocity of flow increases & the lateral pressure decreases (Bernouli effect) Velocity (V) x fluid density (p) & tube diameter (d) is inversely proportional to fluid viscosity (n) |
The Lateral pressure of fluid flowing through a constricted segment of tubing is decreased. An increase in velocity happens simultaneously with decrease pressure. | Bernoulli's Principle |
Air passing through a venturi tube creates what type of pressure and what happens because of that pressure that allows it to pick up gas as it passes over an area of higher pressure? | Low pressure, because of the low pressure when it passes over an area of higher pressure. |
Critical Temperature applies to what? | Gases liquefy if sufficient pressure is applied and the temperature is below a critical value called the critical temperature. A gas cannot liquefy if the temperature is above the critical temperature: for N2O it is 39.5C, for O2 is it -119C |
Explain the Joule-Thompson effect | A physical process in which the temperature of a gas is decreased by letting the gas expand. As a cylinder cools; condensation and ice crystals may be seen |
Saturated vapor pressure | At any given temperature there is a pressure at which the vapor of that substance is in equilibrium with its liquid or solid forms |
In a closed container molecules leaving=molecules entering liquid | Saturated vapor pressure. Higher temperature=higher saturated vapor pressure. |
Vapor pressure in an open container | Vapor pressure is called partial vapor pressure. Boiling point is when vapor pressure=atmospheric pressure. Dependent on heat and pressure. |
Give the volume percent and the partial pressures of the following: Nitrogen (N2) Oxygen (O2) Argon (Ar) Carbon dioxide (CO2) | N2= 78.08%, 593.4mmhg O2= 20.95%, 159.2mmhg Ar=0.93%, 7.1% CO2=0.03%, 0.2mmhg totals 99.9%, 759.9mmhg |
Atmospheric pressure = __, saturated water vapor pressure at 37 C =__ and what percent of atmospheric pressure is that? | 760mmhg, 47mmhg and it is 6% of atmospheric pressure. Partial pressures are from Dalton's Law |
Enflurane | 175mmhg and MAC=1.68% |
Halothane | 243mmhg and MAC=0.75% |
Isoflurane | 239mmhg and MAC=1.15% |
Sevoflurane | 170mmhg and MAC=2.1% |
Desflurane | 669mmhg and MAC=6.0% |
MAC | minimal alveolar concentration. 1 MAC= the minimal alveolar concentration of an inhalation agent at which 50% of the patient's will not respond to surgical stimulation. |
Absolute Pressure | is the sum of all pressure. It is zero referenced against a perfect vacuum. P absoulute = P gauge + P atm |
Gauge Pressure | Is the pressure relateice to the local atmospheric or ambient pressure. It is zero referenced against ambient air pressure. P gauge = P absolute - P atm |
The pressure exerted by the vapor of a substance in contact with its liquid or solid phase in a sealed container. | Vapor Pressure. It is the function of temperature not pressure! |
Saturated Vapor Pressure | When the substance is in dynamic equilibrium with its gaseous and liquid state at a given temperature. In a closed container the molecules leaving liquid state=the number of molecules entering the liquid state. |
Partial Pressure | The pressure exerted by one gas in a mixture of gases. P total = P1+P2+P3+ect. |
The working pressure in a cylinder | Service pressure- given by manufacturer |
Pressure regulator | The mechanical device used to safely control the discharge pressure of a compressed gas from a container. |
STP | Standard temperature and pressure. Standard temperature is 0 C, Standard pressure is 100kPa |
Boiling point | The temperature at which the vapor pressure is equal to the atmospheric pressure. Dependent on heat and pressure. |
Cryogenic Liquid | A liquid with a normal boiling point below -150 C at 1 atm. |
Oxidizing Gas | A gas that can support and accelerate combustion of other materials. |
Conversion 1 atm = | 1 bar = 760 torr = 760mmhg = 14.696psi = 101.325kPa |
1 psi = | 54mmHg |
1mmHg = | 1.36 cm H2O |
Oxygen Tank Pressures and Volumes | D tank=2200 psi --> 412L, E tank=2200 psi --> 660L, H tank=2200psi -->6900L |
Nitrous Oxide Tank Pressures and Volumes | E tank=750 psi --> 1590L, H tank=750 psi --> 16000L |
When is gas considered a compressed gas? | A gas or mixture of gases that, in a container, will have an absolute pressure exceeding 40 psi at 70 F or 21.1 C, or exceeding 104 psi at 130 F or 54.4 C regardless of pressure at 70 F. A liquid w a vapor pressure exceeding 40 psi at 100 F or 37.8 C. |
What are some of the compressed medical gases and what are their uses? | Nitrous Oxide- anesthetic agent, Nitrogen-power equipment, Carbon dioxide-insulflation of abd for laproscopic proceuders, Compressed air-in anesthesia to get FiO2, Helium-expand atelectesis in lungs. |
The design, construction, testing, marking, labeling, filling, storage, handling,maintenance, and transportation of high pressure cylinders is regulated by whom? | The DOT! |
The National Institute of Occupational Safety and Health has regulations on what two compressed gasses? | Nitrous oxide, halogenated agents |
Recommended exposure limits for nitrous is? In a 8 hour work day? | 25 ppm, and 50 ppm for an 8 hour work day--> time weighted work avg. |
Recommended exposure limits for halogenated agents? | Not to exceed 2 ppm for greater than 1 hour. |
If you were to run Nitrous with a halogenated agent? | 0.5 ppm of halogenated agent, and 25 ppm of Nitrous oxide. (from Don's scavenger system lecture) 5 ppm, and 2 ppm no longer than an hour. (from Kevin's Medical gases lecture) |
Some fun facts about Compressed gas cylinders... | Steel or chrome alloy construction. Cylinder walls are 3/8" thick. That safety features for the prevention of wrong gas cylinder connections--> cylinder markings, color coding, Pin Index safety system (PISS) |
Interior hydrostatic pressure testing is done how often? | every 10 yrs. They are tested to 1.66 times their service pressure. Tensile strength, impact test--> cylinders must have up to 10% tensile strength. |
Should I refill my smaller empty cylinder with the larger one? | NO WAY HOSE! It is illegal! Risk for explosion from the heat of compression. The transfer of cylinder contents from a smaller cylinder generates heat and can cause combustion. |
Why should we open the cylinder momentarily before use? Cracking the cylinder? | To clear the outlet of possible dust. |
What should always be attached to the outlet valve? | A regulator device. We can't use the 2200 psi, so the regulator device decreases it to something more manageable. |
What aids in the prevention of wrong gas cylinder connections? | The PISS system or pin index safety system. Two- 5-mm stainless steel pins on the cylinder yoke connector just below the fitting for the valve outlet port. |
Air pin positions are at positions what? Oxygen pin positions are at positions what? Nitrous oxide pins are at positions what? | Air- 1 & 5. Oxygen- 2 & 5. Nitrous oxide- 3 & 5. |
What are two types of connectors at the wall? | Quick coupler- allows for rapid connection and disconnection of fittings and hoses. Diameter Index Safety System (DISS)- gas specific diameter fittings, non interchangeable thread system. |
Characteristics of Gas Cylinders | Color of tank, cylinder markings, pressure relief valves, type of cylinder (size), connectors. |
Color coding of cylinders--> Medical air, medical carbon dioxide, medical helium, medical nitrogen, medical nitrous oxide, medical oxygen | Medical Air-> Yellow, Medical Carbon Dioxide-> Gray, Medical Helium-> Brown, Medical Nitrogen->Black, Medical Nitrous Oxide-> Blue, Medical Oxygen-> Green |
What information needs to be on the cylinder? | Cylinder specifications-regulated by DOT, specification of cylinder construction material, service/working pressure in psi. Cylinder serial number. Registered owner symbol-indicates the original owner of the cylinder. Date of manufacture. |
What is required on all medical gas cylinders that incorporates a mechanism to vent the cylinder's contents before it explodes from excessive pressure. What can be a result of excessive pressure? | Pressure relief valves. Extreme temperatures cause the pressure to increase. Different types are Fusible plug, frangible disc assembly, safety release valve. |
Is made of woodsmetal? | Fusible plug- has a low melting point which allows the escape of the gas in the case of a fire. Can aggravate the fire due to the flammability of the gases released. |
This assembly is designed to break when a certain pressure is exceeded and allows gas to escape through a discharge vent. | Frangible disc assembly |
Safety relief valve | A spring loaded mechanism that opens a discharge pressure relief valve if pressure becomes too high. The valve remains open until the pressure falls below the valve's opening threshold. |
This cylinder is found on the back of the anesthesia machine for emergencies if the central pipeline gas fails and is often found on the patient stretcher for transport with oxygen. | E cylinder. This should always be closed when attached to the back of an anesthesia machine bc anesthesia machine does not know how much is in tank. If cylinder is closed the machine will alarm and when the cylinder is empty it will alarm. |
When does an E cylinder need to be replaced before completely empty? | Around 250-300 psi. |
What can be used to explain gas escaping from a cylinder? | Universal gas law. PV=nRT. PRessure in the cylinder decreases as the # of moles of gas decreases. Remember that a cylinder has a constant volume. |
The volume of gas releases from the cylinder can be estimated using who's law? | Boyle's Law. Pressure and volume are inversely related at a constant temp. P1V1=P2V2. Explains why a large volume of gas is releases from a pressurized cylinder. We can figure out how much gas is in the tank. |
What happens when N2O is placed under a pressure of 750 psi? | It becomes a liquid at room temp. And oxygen only exists and is a gad at room temperature. |
Nitrous Oxide E Cylinder is filled 90-95% capacity in what form? (solid, liquid, gas) | Filled with liquid nitrous oxide form. Nitrous oxide is in an equilibrium between its vapor and liquid state-saturated vapor pressure. The pressure of the vapor exerted upon the liquid state is called the vapor pressure. |
Does the pressure gauge allow us to determine how much N2O is left in the tank? | No, the pressure in the tank will read 745 psi until all of the liquid below the gas has been vaporized. At that point the residual vaporized gas is expended and the pressure in the tank will decrease rapidly. The tank is considered empty. |
The amount of N2O remaining in the tank must be determined by what? | The weight. Subtract the tare wt of the empty tank from the wt of the tank in question. The difference is the wt of the residual N2O. |
As gas leaves the N2O cylinder the liquid below the gas will continue to vaporize, what happens as a result of this? | Heat is lost when a liquid vaporizes- this is called the latent heat of vaporizes. This causes a drop in the temp within the cylinder referred to at the joule-Thompson effect. The pressure within the tank with decrease-->Gay-Lussac's Law |
More info on Nitrous Oxide | with sufficient humidity in the surrounding atmosphere moisture or even frost may collect on the outside surface of the cylinder over the portion that is filled with liquid N2O. Can provide an indication of the remaining volume. |
H Cylinder | Source for small or infrequently used pipeline systems. Intermediate to long term use. Hospitals store O2 H cylinders in bulk to use as a backup source in case the pipeline fails. |
Convert high pressures to "working pressures" | Reducing valves. 50 psi is working pressure. Single stage or dual stage. |
Pressure regulators | Bourdon Gauge-high pressure readings, works regardless of position of tank. Flowmeters: Thorpe-low pressure, 50 psi, only only works in upright position. |
What are the three main components of the bulk supply systems? | Central supply of gas, pipelines to transport the gasses, appropriate end point connenctors. |
If a higher vapor pressure agent is placed in a vaporizer designed for a lower vapor pressure agent, what will the concentrated delivered be? higher or lower? | The concentration delivered will be higher than the dialed setting. |
If a lower vapor pressure agent is placed in a vaporizer designed for a higher vapor pressure agent, what will the concentration delivered be? Higher or lower? | The concentration delivered will be lower than the dialed setting. |
If Iso is added to a halothane vaporizer the delivered concentration will be what? | About the same (per kevin's notes) |
Carrier gases O2, Air, and N2O are measured in what? | LPM, anesthetic agents measured in % of atmospheric pressure. You have to put them in the same value, or mmHg |
Atomic number | Number of protons found in the nucleus of an atom |
Element | Matter composed of atoms that all have the same atomic numbers |
Smallest unit of an element to retain all the chemical properties of that element | Atom- composed of electrons, neutrons, and protons |
Particle in the nucleus with a positive charge of +1 and an atomic mass number of 1 is a what? | A Proton! |
A non charged nuclear particle with the same mass as the proton is what? | Neutron |
Electron | Negatively charged particle with a mass of 1/1837 of that of a proton. |
What determines the chemical properties of an atom? | Electron |
Atomic Forces- and electron is held around the nucleus by what? | Electromagnetism |
Quantum numbers, there are four. What are they and what do they signify? | n,l,m,s- signifies the actions of the electrons in orbit. |
Quantum number n=__, l=__, m=__, s=__? | n=principle number, size of the orbit. l=angular number, shape of the orbit. m=magnetic number, orientation in space (observed in magnetic field). s=spin of the electron |
What tells the number the protons? | The atomic number |
Atomic mass is what? | The number of protons + the number of neutrons. Proton or neutron has the mass of 1 amu. |
Amu= | Atomic mass unit. Da -Dalton. 1/12th of the mass of 1 atom of carbon-12. |
What atoms of the same element have the same # of protons and same atomic #, but differ in the # of neutrons? They have a different atomic mass. | Isotopes |
Physical properties of Isotopes | Protons=electrons, nearly identical chemical behavior (mainly determined by electrons). The greater the proton/neutron ratio the less stable the nucleus-->nuclear decay. |
Do ions carry a charge? | Yes, the contain a net electrical charge. Anion=Negative charge and are attracted to anodes. Cation=Positive charge and attraction to cathodes. |
If an atom loses an electron, and they now contain more protons than electrons, what is the net overall charge of that atom? | Positive charge. |
This type of gas analyzer is used in anesthesia and determines the mass/charge ratio. The sample must be in a gas form (vaporized)? | Mass spectrometry-fundamentals of gas phase ion chemistry |
How mass spectrometry works? | Sample is broken down (ionized), & this gives them an electrical charge. They pass through a magnetic field that pulls the ions causing a curve. Lighter ions go farther than heavier. Ion mass/charge ratio is calculated based on the variance of deflection. |
What is the valance shell of an atom? | The outer most energy level of an atom. |
How does valance shell affect how reactive an atom is? | Elements with a full outer shell are very unreactive, and elements with an almost full or almost empty outer shell tend to be very reactive. The atoms that travel furthest from nucleus have the greatest energy and determine physical properties. |
What determines the physical properties of an atom? Not chemical. | Electrons |
What is the octet rule? | Atoms combine in such a way to have eight electrons in their valance shells-same as a noble gas. |
Atoms attempt to achieve stability by the octet rule and what happens in this process? | A bond is formed. Stability is a full outer shell and is done by forming a bond with another atom. |
Does bond forming require energy? | YES! |
Bond dissociation energy (Kcal/mole) is what? | The energy required to break a bond. It is easier to measure bond dissociation than energy to make a bond. |
What are the two main types of bonds? | Covalent and Ionic- Involves electrons |
What type of bond shares electrons? | Covalent bonds |
What is polarity? | Difference in electrical charge. Electronegativity difference that is less than 1.67 or between 0.5 to 2.1. Electronegativity exists between most covalent bonds unless pure covalent bond. |
Pure covalent bond fun facts | electronegativity difference of 0. Usually non-soluble, and electrically non conductive. Is a good insulator. |
What is the force that gives atoms the affinity to bind to electrons? | Electronegativity- Oxygen is 3.5, Carbon is 2.5 and hydrogen is 2.1. Carbon/hydrogen bond have equal sharing of electrons. |
The bond between hydrogen and oxygen to make water is what type of bond? | Covalent bond. Hydrogen atoms have slight positive charge. Electrostatic attraction exists between oxygen of one molecule and hydrogen of another molecule. |
What happens with an ionic bond? | Electron is given up to another. One atom then becomes negative while the one becomes positive. A negative atom is attracted to a positive atom by electrostatic forces. |
Common Salt NaCl is what type of bond? | Ionic bond- stronger than hydrogen bonds and similar to covalent bonds. Pure ionic bond does not exist. |
Ionic bonds tend to have what physical properties? | High melting point, tend to be soluble in water, conduct electricity. |
Electrostatic bonds result from | 2 ionized groups of opposite charge, and polarized molecules. |
Extensive properties, Intensive properties, and Colligative properties are physical properties pertaining to what? | Extensive-mass and volume. Intensive-density and concentration. Colligative-property of solutions. |
Density | A property of gas. D=mass/volume. Density is the physical property that allows for the proper function of an open scavenger system on an anesthesia machine. |
Colligative properties | Determines how the properties of a liquid solution change depending on the concentration of the solute in it. 4 properties-vapor pressure, freezing pt depression, boiling pt elevation, osmotic pressure. |
Solutions show a __ in melting point as the amount of solute is increased. | A decrease in melting point as the amount of solution is increased. Thing why we put salt down when we are expecting an ice storm. More solute,easier to melt. |
Freezing point depression is the difference between..... | Diff between the freezing pts of a pure solvent & a solution mixed with a solute. It is directly proportional to the molal concentration of the solution according to the equation Kf for water is 1.86 K*kg/mol. |
Freezing point depression Kf for water is 1.86 K*kg/mol is explaining what? | Per mole of solute dissolved in a kg of water the freezing point depression is 1.86 kelvins. (more solution in liquid, takes longer to freeze) |
Solution shows a __ in boiling pt as the amount of solute is increased? | An increase. A solution will have a higher boiling pt than that of a pure solvent. (don't know why we were always told to put in water to make it boil faster) |
What type of pressure is produced by a solution in a space that is enclosed by a differentially permeable membrane? | Osmotic Pressure. The greater the solute; the greater the concentration gradient; the greater the osmotic pressure. B/P cell hydration |
Vapor Pressure can be looked at like the pressure=elastic collisions with walls of a container. If we double the # of atoms in a container what will happen? | The number of collisions will double against the wall as well. If we were to double the volume instead, the # of collisions would decrease in half. |
Faster molecules will hit the wall__, Larger faster molecules hit the walls with__? | Faster=more often. Larger, faster=hit wall with more force. |
Larger molecules traveling the fastest in one container would have what type of vapor pressure compared to smaller, slower molecules in another? | It would have a higher vapor pressure. |
A solution of a solid non volatile solute in a liquid solvent shows a decrease in vapor pressure above the solution as the amount of solute is __? | Increased. |
How is vapor formed? | By molecules escaping from a liquid. |
If you were to place a substance in an evacuated, closed container. The pressure in the space above the liquid would do what? | It would increase from zero and eventually stabilize at a constant value. Measurement 1 torr=1 mmHg |
Vapor pressure relates to the rate atoms and molecules escape from a liquid. The higher the vapor pressure of a substance, the more __ the substance? | The higher the vapor pressure the more volatile the substance. Molecules will escape faster from a liquid, and it will have a lower boiling pt. Iso, sevo have high vapor pressures, Des has the highest! |
The point where the pressure of a gas is equal to its liquid form, this is relevant in a closed container. | Saturation vapor pressure. Number of molecules leaving liquid=number of molecules entering (condensing) into the liquid. |
In an open container what is the pressure or opposing force? | Atmospheric pressure. |
Latent heat of vaporazation | The number of calories needed to convert 1 g of liquid to vapor. The temp of the remaining liquid will drop as vaporization proceeds. Heat is a product of vaporization, if no heat is added,the hear is taken from the substance. |
VP in a closed container is independent of atmospheric pressure so what does it depend on? | Depends only on the physical characteristics of the liquid, and its temperature. The more volatile the agent, the more energy (heat)is created (used). |
What gas is inert at room temperature and liquid at room temperature and pressures greater than 745 psi? | Nitrous Oxide. Change tank when it reaches 745 because you have no idea how much gas is actually left. |
What are forms of energy? | Kinetic=energy of motion. Chemical=chemical bonds. Electrical=due to its charge. Thermal=due to its heat. Nuclear=due to the instability of the nuclei of its atoms. Potential=due to the position of the object relative to other objects. |
What explains the total inflow of energy into a system must equal the total outflow of energy from the system, plus the change in the energy contained within the system. Energy can be converted, but cannot be created nor destroyed. | Conservation of energy |
What is the first law of thermodynamics? | Energy cannot be created nor destroyed. Based on the conservation of energy. Amount of energy if a system=energy added (heat)- work done. Energy is neither created or lost; just changed from one form to another. |
What is the second law of thermodynamics? | The energy available after a chemical reaction is less than that at the beginning of a rxn. Entropy-amount of unusable energy within a system. As energy is transferred form one form to another, some is lost as heat;and entropy increases. |
Is continuous motion without a change of energy possible? | Heck NO! |
Third law of thermodynamics | At absolute 0, entropy would=0. Continuous motion without adding or losing energy is possible or, no change of energy would exist within a system. The system would remain constant. Absolute 0 does not exist. |
Movement of hear only flows in one direction what is that direction? | Flows from hot to cold ALWAYS! Flow of heat stops at absolute 0. |
What are the mechanisms of heat transfer? | Conduction, convection and radiation. What about evaporation? Evaporation is not a true heat transfer mechanism. |
Conduction | Transmission of heat across matter. Denser substances are usually better conductors;metals are excellent conductors. Heat loss through direct contact. |
Radiation | Heat loss due to temperature gradient. Temp less than 98.6 F |
Evaporation | Sweating, respiration. A chemical rxn. Sweat vaporizes pulling heat from body and evaporates. Cooling down body. If sweat did not evaporate then sweating would not cool the body down. |
Convection | Constant mvt of one of the surfaces. Wind: as your body heat warms up the air around you, the wind replaces that air with cooler air thus creating a greater temp gradient. Can work in the reverse order-convection oven. Not a chemical process. |
If you jump into water to cool off, is the water what is actually making you cooler? | No, your warming the water up, because the water is pulling the heat off of your body, thus making you feel cooler. |
The concentration or partial pressure in the lungs is assumed to be the same as in where? | The brain. Because of how quickly equilibrium is achieved. Due to high lipid solubility of anesthetic agents. |
What is necessary to produce lack of movement in 50% of anesthetized patients upon surgical stimulation and is expressed as a percentage of 1 atm. | Minimal alveolar concentration (MAC) |
MAC-BAR | The minimal alveolar concentration that blocks autonomic responses to surgical stimulation. 1.3 times MAC |
MAC-awake | Concentration at which 50% of anesthetized patients will respond to commands. Level of awareness. 1/2 the MAC for recall. |
In regards to MAC... | Equilibrium is reached quickly between body compartments. The faster the lung (brain) concentration the faster the anesthesia is achieved. The quicker the concentration falls the quicker the patient emerges. |
Who said that the solubility of a gas in a liquid decrease as temperature increases. More inhalation agent will dissolve in the blood if the patient is hypothermic. | Le Chatelier's Law- more gas is in a liquid when water is cold than when it is hot. If a patient is hyperthermic less agent dissolved in blood and more anesthetic gas has to be used to achieve same effect. |
What are some factors in which influence the ability of a gas to anesthetize a patient? | Machine-related factors, Drug related factors(blood gas solubility),Ventilation factors(concentration or dose, second gas effect), Tissue related factors(oil/gas solubility), Circulatory factors, Metabolism. |
Low liter flows of carrier gas deliver the anesthetic more slowly at the beginning of induction is what type of factor? | Machine related factor. 2L of O2 will take longer to deliver 2% Sevo than 10L O2. |
What indicates the speed of uptake and elimination of a drug? | Blood/gas solubility |
Blood/gas solubility | Reflects the portion of anesthetic that will bind to blood compartments & not readily enter tissues vs. that which will leave the blood for the tissues. More soluble the drug, high blood/gas coeff the slower the brain uptake=slower onset of anesthesia |
Blood/gas solubility coefficients at 37 C | H=2.3 E=1.9 I=1.4 S=.6 N=0.47 D=0.42 |
Anesthetic agents are like any other diffusible drugs in that? | Anesthetic agents move down a concentration gradient until equilibrium is achieved. |
What is the ventilation effect when giving inhalation agents? And what can hinder this? | The faster and more deeply a patient breathes or is ventilated, the faster the onset/emergence. Lung pathology can hinder anesthesia drug administration. |
The higher the concentration of anesthetic gas delivered the __ anesthesia is achieved. | Faster |
Nitrogen being 34 times less soluble than N2O has what effect? | More soluble N2O diffuse from the alveoli to the blood faster then Nitrogen leaves the blood. |
What do the alveoli do so that the alveolar concentration of agent remains high? | The alveoli shrink. Permits more rapid uptake of agent by the blood. Ficks law of diffusion. |
What is the second gas effect? | A phenomenon where a agent with a slow onset is given with an agent with a fast onset, (N2O). The agent with the slow onset achieves anesthetic levels more quickly than if it had been used alone. Fick's Law. |
Why is the administration of 100% O2 for 3-5 min upon discontinuing nitrous important? | Diffusion Hypoxia- temporary hypoxia upon discontinuation of nitrous oxide if breathing room air. |
What indicates the potency of a drug? | Oil/gas solubility |
This higher the oil/gas solubility the __ the drug. | The more potent the drug. At the tissue level, the lipid solubility allows it to penetrate membranes and produce action. |
What are the oil/gas solubility coefficients? | N=1.4 D=18.7 S=50 E=98 I=99 H=224 |
What is necessary for the drug to equilibrate between lungs and brain? | Circulation. Greater CO leads to greater lung perfusion and more of the drug absorbed into the blood, thus slower rise in brain concentration. The longer the anesthetic is given the more that reaches the vessel poor group. |
What agent is associated with hepatoxicity? | Halothane |
What agent is associated with nephrotoxicity, although incidents are rare? | Sevoflurane |
How are most of the agents eliminated from the patient? | They are breathed off. Anesthetic leaves the body via the blood and exits the lungs with ventilation, diffusion takes place down the gradient. |
Anesthetized patients should never receive less than how much O2? | 30%. |
This agent reacts with CO2 scrubber and takes place with heat and fresh gas flows less than 2/Lpm. The by product is compound A. | Sevoflurane |
This has been known to be produced after the use of des and sevo with sodalime. | Carbon Monoxide- use of amsorb and proper maintenance of machine will decrease the likelihood of this happening. |
What agent equlibrates with all tissues within 2.5 hours? | Nitrous Oxide |
When N2O is used what happens to the gas spaces? | Gas spaces change pressure or volume. These spaces are nitrogen rich and Nitrogen is 34 times less soluble than N20. |
Why is the onset and emergence of anesthetic agents faster in pediatrics? | Differences in blood/gas and blood/tissue partition coefficients/ Alveolar ventilation in relation to FRC is greater. Greater distribution of CO to the brain. |
Nitrous oxide is an organic/inorganic molecule? | Inorganic- only one |
Halothane is a halogenated what? | Hydrocarbon |
Excluding halothane, what are the other anesthetic agents? | Halogenated ethers |
Halogenated agents are... | Less flamable |
Chlorine and flourine chemistry | Chlorine is extremely toxic. Flourine increases speed of onset and decreased recovery times. |
Inhaled anesthetics produce what type of effects? | Both amnesia and immobility. Possibly enhance backround K currents in tandem-pore-domain, weak inward rectifying K channels. Neuronal nicotinic ACh receptors have also been shown to he highly sensitive to inhalational anesthetics. |
Inhalation anesthetics working on receptors | Reduce spontaneous action potential firing of spinal neurons via glycine receptors & y-aminobutyric acid type A (GABA) receptors. |
GABA is an abundant receptor in the CNS and is what type of channel? What happens to this receptor and how does it produce its effects? | A ligand gated chloride ion channel. Agonism of this receptor by volatile agents results in enhanced chloride conductance that leads to inhibitory action on local neurons. |
What does Iso, Des, and Sevo do cardiovascular system? | Iso-BP decrese, HR increase. Des-BP decrease, HR NC or increase. Sevo- BP decrease HR NC. |
What does Iso, Des, and Sevo do the Respiratory system? | Iso-TV decrease RR Increase. Des-TV decrease RR increase. Sevo-TV decrease RR increase. |
What does Iso, Des, and Sevo do the cerebral system? | Iso-ICP increase. Des-ICP increase. Sevo-ICP increase |
What does Iso, Des, and Sevo do the renal system? | Iso-BF, UO, GFR decrease. Des- BF, UO, GFR decrease. Sevo-BF, UO, GFR decrease. |