Term
| Describe the three states of matter |
|
Definition
|
|
Term
|
Definition
| the change of state from liquid to gas |
|
|
Term
| What does vaporization require in order to change from a liquid to a gas |
|
Definition
| "heat energy and according to the First Law of Thermodynamics, this heat energy must come from the surroundings" |
|
|
Term
|
Definition
| "a type of vaporization whereby heat is taken from the air surrounding the liquid thereby cooling the air - i.e. sweat evaporation which cools of the body by transferring the body's heat to water, which is a good conductor of heat and transferring that heat into the surrounding air" |
|
|
Term
|
Definition
| The opposite of evaporation whereby a gas turns back to a liquid. condensation gives heat back to the surroundings |
|
|
Term
| What happens to kinetic energy when a solid is heated |
|
Definition
| it increases and this added internal energy increases molecular vibrations |
|
|
Term
| How is a solid changed into a liquid |
|
Definition
| "kinetic energy increases and this added internal energy increases molecular vibrations and if enough heat is applied then the intermolecular attractive forces weaken adn at some point, molecules will break free of their rigid structure and the solid will change into a liquid" |
|
|
Term
| What is the extra heat needed to change a solid to a liquid |
|
Definition
|
|
Term
| What does all matter posess and what is it called? |
|
Definition
| energy and it is called internal energy |
|
|
Term
| What are the two major types of internal energy |
|
Definition
| energy of position which is potential energy and energy of motion which is kinetic energy |
|
|
Term
| What is most internal energy in solids and liquids |
|
Definition
| "although all matter has some kinetic energy, most internal energy in solids and liquids is potential energy" |
|
|
Term
| What is the potential energy within solids and liquids a result of |
|
Definition
| strong attractive forces between molecules. These intermolecular forces cause rigidity in solids and cohesiveness and viscosity in liquids |
|
|
Term
| What is the internal energy of gases |
|
Definition
| most of their internal energy is kinetic....the attractive forces are week and the molecules are moving all the time |
|
|
Term
| What is the relationship between temperature and kinetic energy? |
|
Definition
| "The temperature of a gas, with most of its internal energy spent keeping molecules in motion, is directly proportional to its kinetic energy whereas the temperature of solids and liquid represent only part of their total internal energy" |
|
|
Term
| What is the international temperature scale? |
|
Definition
| SI (systeme internationale) with zero Kelvin |
|
|
Term
| How many degrees are there between freezing and boiling? |
|
Definition
| 100 making it a centrigrade scale or 100 step scale |
|
|
Term
| What is the difference between kelvin and celcius scales? |
|
Definition
| "In Kelvin, 0 degrees is as close to absolute zero as possible whereas 0 celcius is freezing point of water. celcius also has a 100-step system with 100 degrees between freezing and boiling" |
|
|
Term
|
Definition
| The temperature with which kinetic molecular activity stops |
|
|
Term
| what is the absolute zero temperature on the celcius scale |
|
Definition
|
|
Term
| How is kelvin converted to celcius? |
|
Definition
|
|
Term
| How is celcius converted to kelvin |
|
Definition
|
|
Term
| What is absolute zero on the Fahrenheit scale |
|
Definition
|
|
Term
| What is the formula to convert Fahrenheit to Celcius |
|
Definition
|
|
Term
| How do you convert celcius to Fahrenheit |
|
Definition
|
|
Term
| What is the First Law of Thermodynamics |
|
Definition
| energy can be neither created nor destroyed |
|
|
Term
| "What happens if a substance gains or loses energy, based on the first law of thermodynamics" |
|
Definition
| "any energy a substance gains must exactly equal the energy lost and if a substance loses energy, this loss must be offset by an equal gain in the energy of its surroundings" |
|
|
Term
| What is the formula for the first law of thermodynamics |
|
Definition
| "U=E+W U is internal energy of an object, E is the energy transferred to or from and W is the external work perfomed on the object" |
|
|
Term
| "In the forumla for the first law of thermodynamics, what is E, or energy, equivalent to?" |
|
Definition
| "heat because heating is the transfer of internal energy from a high-temperature object to a low-temperature object. based on this formula, you can increase the internal energy of an object by heating it or by performing work on it" |
|
|
Term
| What does the first law of thermodynamics tell us regarding when two objects exist at different temperatures |
|
Definition
| heat will move from the hotter object to the cooler object until the objects' temperatures are equal. two objects with the same temperature exist in thermal equilibrium |
|
|
Term
| What are the four ways heat transfer can be affected |
|
Definition
| "conduction, convection, radiation and evaporation/condensation" |
|
|
Term
| How does heat transfer in solids mainly occur |
|
Definition
| via conduction which is the transfer of heat by direct contact between hot and cold molecules |
|
|
Term
| What is conduction heat dependent upon |
|
Definition
| it depends on both the number and force of molecular collisions between adjoining objects |
|
|
Term
| how is heat transfer beween objects quantified by |
|
Definition
| using a measure called thermal conductivity |
|
|
Term
| Which types of substances have high thermal conductivity and which have lower ones? |
|
Definition
| "metals - transfer heat rapidly therefore if you touch metal like silver, copper, aluminum, iron, lead, etc. it feels cold because the object is ""taking"" your heat. vs. solids and liquids exhibit low thermal conductivity - air, wool cork board, fiberglass all have low thermal conductivity with ice, glass, concrete, water, hydrogen, helium, snow all in the middle" |
|
|
Term
| How is heat transferred in both liquids and gases |
|
Definition
| mainly by convection which involves the mixing of fluid molecules at different termperatures. air (even though poor conductor of heat) can transfer heat by convection by being warmed in one location and then circulated to carry heat elsewhere |
|
|
Term
|
Definition
| "solid internal order, molecules move less and maintain shape because atoms are kept in place by strong mutual attractive forces called van der waals forces" |
|
|
Term
|
Definition
| "mutual attraction but much weaker than solids, molecules move about freely which explains why they take shape of container and are capable of flow, liquids are similar to solids in that they are dense and cannot easily be compressed" |
|
|
Term
|
Definition
| "molecular attractive forces are weak, lack restriction to movement, exhibit rapid, random motion with frequent collisions. No inherent boundaries, easily compressed and expanded and they can flow. " |
|
|
Term
| Which two states of matter are considered fluids |
|
Definition
| liquids and gases because gases and liquids can both flow |
|
|
Term
| What are fluid movements carrying heat energy called |
|
Definition
|
|
Term
| how does radiant heat transfer |
|
Definition
| It transfers without direct contact and occurs even when in a vacuum such as the sun heating the earth |
|
|
Term
| How is radiant energy similar to that of light |
|
Definition
| "radiant energy given off by objects at room temperature is mainly in the infrared range, which is invisible to the human eye. Whereas objects such as an electrical stove burner or a kerosene heater radiate some of their energy as visible light. Commonly used to keep newborn infants warm." |
|
|
Term
| What is the formula that defines the rate at which an object gains or loses heat by radiation |
|
Definition
|
|
Term
| "In the radiation energy equation (E/t=ekA(T2-T1) what is E/t, what is e, k, A, T1, T2" |
|
Definition
| "E/t is heat loss or gain per unit time, e is the emissivity of the object or its relative effectiveness in radiating heat. k is StefanBoltzmann constant (based on mass and surface area) A is the area of the radiating object and T1 and T2 are temperatures of environment and object respectively - for an object with a given emissivity (relative effectiveness in radiating heat) the larger the surface area and the lower the surrounding temperature, the greater is the radiant heat loss per unit time" |
|
|
Term
| What does freezing do with regard to energy to the surroundings |
|
Definition
| "just as melting requires large amounts of externally applied energy, you would expect freezing to return this energy to the surroundings" |
|
|
Term
| What does the First Law of Thermodynamics say about energy required to freeze and melt a substance |
|
Definition
| That they must equal each other and therefore the freezing and melting points of a substance are the same |
|
|
Term
|
Definition
| variations in liquid pressure within a container producing upward supporting force |
|
|
Term
| "What helps explain viscosity, capillary action and surface tension" |
|
Definition
| "although melting weakens intermolecular bonding forces, liquid molecules still attract one another adn the persistence of these cohesive forces among liquid molecules explain the physical properties of viscosity, capillary action and surface tension" |
|
|
Term
| What does the pressure exerted by a liquid depend on |
|
Definition
| both its height (depth) and weight density (weight per unit volume) |
|
|
Term
| what is the equation form of pressure exerted by a liquid |
|
Definition
|
|
Term
| pL=h x dw - what do the letters stand for |
|
Definition
| "pL is statis pressure exerted by the liquid, h is the height of the liquid column, and dw is the liquid's weight density" |
|
|
Term
| What is Pascal's principle |
|
Definition
| liquid's pressure acts equally in all directions |
|
|
Term
| What is Archimede's principle |
|
Definition
| buoyancy - liquids exert buoyant force because the pressure below a submerged object always exceeds the pressure above it and this difference in liquid pressure creates an upward or supporting force. This buoyant force must equal the weight of the fluid displaced by the object |
|
|
Term
| How is the buoyant force calculated as with B being buoyant |
|
Definition
|
|
Term
| What happens if the weight density of an object is less than that of water |
|
Definition
| It will displace a weight of water greater than its own weight and the buoyant force will overcome gravity and the object will float |
|
|
Term
| What happens if the weight density of an object is greater than that of water |
|
Definition
|
|
Term
| How is Achimides' principle used in the clinical setting |
|
Definition
| It is used to measure the specific gravity of certain liquids |
|
|
Term
| What helps keep solid particles suspended in gases |
|
Definition
| "buoyancy. these suspensions, called aerosols, are important in the role of the respiratory therapist" |
|
|
Term
|
Definition
| the force opposing a fluid's flow |
|
|
Term
| What is a fluid's viscocity in direct proportion to |
|
Definition
| "the cohesive forces between its molecules. the stronger these cohesive forces, the greater is the fluid's viscosity. the greater a fluid's viscosity the greater is its opposition to flow" |
|
|
Term
| When is viscosity most important |
|
Definition
| when fluids move in discrete cylindrical layers called streamlines |
|
|
Term
| What is a pattern of motion whereby fluids move in discrete cylindrical layers called streamlines |
|
Definition
|
|
Term
| What does laminar flow consist of |
|
Definition
| concentric layers of fluid flowing parallel to the tube wall at velocities that increase toward the center |
|
|
Term
| What is the difference in velocity of the layers within laminar flow called |
|
Definition
|
|
Term
| "What is the shear rate, the difference in velocity of the layers within laminar flow a measure of" |
|
Definition
| how easily the layers separate |
|
|
Term
| How easily the layers of shear rate separate are dependent upon which two factors |
|
Definition
| the pressure pushing or driving the fluid called the shear stress and the viscosity of the fluid |
|
|
Term
| "In uniform fluids such as water or oil, how is viscosity related to temperature" |
|
Definition
| the viscosity varies with temperature |
|
|
Term
| why does viscosity vary with temperature in uniform fluids |
|
Definition
| "because higher temperatures weaken the cohesive forces between molecules, heating a uniform fluid lowers viscosity. a lower temperature increases its viscosity (like a car engine in the morning, the oil is too viscous to move through the engine)" |
|
|
Term
| How much higher is the viscosity of blood compared to water and why |
|
Definition
| blood has a viscosity approximately five times greater than water because blood is a complex fluid that contains not only liquid but cells in suspension |
|
|
Term
| Why does the heart work harder to pump blood than it would if it were pumping water |
|
Definition
| becasue the heart must perform more work if when blood viscosity increase as occurs with polycythemia |
|
|
Term
| What is the attractive force between like molecules called |
|
Definition
|
|
Term
| what is the attractive force between unlike molecules |
|
Definition
|
|
Term
| How can the forces of adhesion and cohesion be observed |
|
Definition
| by placing a liquid in a small-diameter tube where the top of the liquid forms a curved survace or meniscus. when the liquid is water the meiscus is concave because the water molecules at the surface adhere to the glass more strongly than they cohere to each other but mercury meniscus is convex because the cohesive forces pulling the mercury atoms together exceed the adhesive forces trying to attract the mercury to the glass |
|
|
Term
|
Definition
| a force exerted by like molecules at a liquid's surface |
|
|
Term
| What is surface tension quantified by? |
|
Definition
| "measurement of the force needed to produce a ""tear"" in a fluid surface layer." |
|
|
Term
| "For a given liquid, how does surface tension vary?" |
|
Definition
| "It varies inversely with temperature thus, the higher the temperature, the lower is the surface tension" |
|
|
Term
| What does surface tension do the the pressure inside a ball? |
|
Definition
| "like a fist compressing a ball, surface tension increases the pressure inside a liquid drop or bubble. Laplace's Law states that this pressure varies directly with the surface tension of the liquid and inversely with its radius." |
|
|
Term
| What plays a key role in the mechanics of ventilation |
|
Definition
| "because the lungs alveoli resemble clumps of bubbles, it follows that surface tension plays a key role in teh mechanics of ventilation" |
|
|
Term
| What does abnormality of alveolar surface tension result in? |
|
Definition
| Collapse of alveoli due to high surface tension |
|
|
Term
|
Definition
| "a phenomenon in which a liquid in a small tube moves upward, against gravity" |
|
|
Term
| What two forces does capillary action involve? |
|
Definition
| both adhesive and surface tension forces |
|
|
Term
| What does the adhesion of water molecules to the walls of a thin tube cause |
|
Definition
| an upward force on the liquid's edges and produces a concave meniscus |
|
|
Term
| "Because surface tension acts to maintain the smallest possible liquid-gas interface, instead of just the edges of the liquid moving up, what happens" |
|
Definition
| the whole surface is pulled upward |
|
|
Term
| What are two applications of capillary action? |
|
Definition
| the basis for blood samples obtained by use of a capillary tube adn the absorbent wicks used in sme gas humidifiers |
|
|
Term
| What are the two forms of vaporization |
|
Definition
|
|
Term
| What is the boiling point of a liquid |
|
Definition
| the temperature at which its vapor pressure equals atmospheric pressure |
|
|
Term
| What happens to its molecules when a liquid boils |
|
Definition
| its molecules must have enough kinetic energy to force themselves into the atmosphere against the opposing pressure |
|
|
Term
| What causes a greater boiling point |
|
Definition
| "because the weight of the atmosphere retards the escape of vapor molecules, the greater the ambient pressure, the greater is te boiling point" |
|
|
Term
| What happens to the boiling point when atmospheric pressure was low |
|
Definition
| "liquid molecules escape more easily, and boiling occurs atlower temperatures " |
|
|
Term
| WHat is the energy required to vaporize a liquid |
|
Definition
| the latent heat of vaporization |
|
|
Term
| what is the number of calories required to vaporize 1 g of a liquid at its normal boiling point |
|
Definition
| latent heat of vaporiztion |
|
|
Term
| Why does vaporization require more energy than melting |
|
Definition
| melting weakens attractive forces between molecules but vaporization eliminates them. elimination of these forces converts essentially all of a substances' internal energy into kinetic energy |
|
|
Term
|
Definition
| a liquid can change into a gas at temperatures lower than its boiling point |
|
|
Term
| "when at temperatures lower than the boiling point, how does water enter the atmosphere?" |
|
Definition
| "through evaporation. the liquid molecules are in constant motion, as in the gas phase. although this kinetic energy is less intense than in the gaseous state, it allows some olecules near the surface to escape into the atmosphere" |
|
|
Term
| what is the invisible gaseous form of water called and which other forms is it distinguished from |
|
Definition
| molecular water vs visible particulate water such as mist or fog |
|
|
Term
| Molecular water obeys the same physical principles as other gases and therefore exerts a pressure called what |
|
Definition
|
|
Term
| does evaporation require heat |
|
Definition
| "yes - the heat energy required for evaporationn comes from the air next to the water surface. As the surrounding air loses heat energy, it cools. This is the principle of evaporation cooling" |
|
|
Term
| What happens to water vapor molecules inside a closed container |
|
Definition
| "it continues to enter the air unti it can hold no more water. At this point, the air over the water is saturated with water vapor. vaporization does ot stop once saturation occurs. instead, for every molecule escaping into the air, another returns to the water reservoir. These conditions are referred to as a state of equilibrium" |
|
|
Term
| What factor influences evaporation the most |
|
Definition
|
|
Term
| WHat two ways does temperature affect evaporation |
|
Definition
| "the warmer the air, the more vapor it can hold therefore the capacity of air to hold water vapor increases with temperature. the warmer the air contacting a water surface, the faster is the rate of evaporation. second, if water is heated its kinetic energy is increased and thus more molecules are helped to escape from its surface. 1-capcity to hold molecular water is increased 2 - water vapor pressure is increased" |
|
|
Term
| What does water vapor pressure represent |
|
Definition
| the kinetic activity of water molecules in air |
|
|
Term
| What is absolute humidity |
|
Definition
| measured by weighing the water vapor extracted from air using a drying agent |
|
|
Term
| What is relative humidity |
|
Definition
| the ratio of its actual water vapor content to its saturated capicity at a given temperature |
|
|
Term
| "At 100% relative humdity, what does even slight cooling of gas cause?" |
|
Definition
| the water vapor to return back to a liquid state called condensation which deposits on any available surface which could even include particles suspended in the gas |
|
|
Term
| What does condensation do with regard to temperature |
|
Definition
| "returns heat to and warms the surrounding environment, whereas vaporization of water cools teh adjacent air" |
|
|
Term
| What is the temperature at which condensation begins |
|
Definition
|
|
Term
| what happens if a saturated gas is cooled below its dew point |
|
Definition
| it causes increasingly more water vapor to condense into liquid water droplets |
|
|
Term
| What is the influence of pressure on vaporization |
|
Definition
| "if the surrounding air pressure is high, there will be more opposing air molecules and vaporization will decrease" |
|
|
Term
| WHat is the influence of surface area on a gas |
|
Definition
| "The greater the available surface area of the gas in contact with air, the greater is the rate of liquid evaporation. i.e. dry air water on flat plate vs. moist air and liquid in a glass" |
|
|
Term
| What properties of gases are shared with liquids and how are gases different? |
|
Definition
| "gases exert pressure, are capable of flow and exhibit the property of viscosity. unlike liquids, gases are readily compressed and expanded and fill the spaces available to them through diffusion" |
|
|
Term
| Why is most of a gas's internal energy kinetic energy |
|
Definition
| because a gas's intermolecular forces of attraction are so weak |
|
|
Term
| WHat is the velocity of gas molecules directly proportional to |
|
Definition
|
|
Term
| what happens as a gas is warmed |
|
Definition
| "its kinetic activity increases, its molecular collisions increase, and its pressure rises. when a gas is cooled, molecular activity decrees, particle velocity and collision frequency decline, and the pressure drops" |
|
|
Term
|
Definition
| "states that 1 g atomic weight of any substance contains exactly the same number of atoms, molecules, or ions. " |
|
|
Term
|
Definition
| standard temperature and pressure dry |
|
|
Term
| what is the ideal molar volume of any gas at standard temperature and pressure dry (STPD) |
|
Definition
|
|
Term
|
Definition
| the ratio of a substance's mass to its volume. dense substance has heavy particles packed closely together. and a low density substance has a low concentration of light atomic particles er unit volue. |
|
|
Term
| what is a good high and low density gas example |
|
Definition
| high density - uranium and low density - hydrogen |
|
|
Term
| "In the clinical setting, what is often substituted for mass?" |
|
Definition
| weight and thus weight density is actually measured |
|
|
Term
| what is the most common unit of weight density in gases |
|
Definition
|
|
Term
| What does weight density equal |
|
Definition
|
|
Term
|
Definition
| the process whereby molecules move from areas of high concentration to areas of low concentration |
|
|
Term
| what is the driving force behind diffusion |
|
Definition
| kinetic energy because gases have high kinetic energy so they diffuse most rapidly |
|
|
Term
| "Besides gases, where else does diffusion occur" |
|
Definition
| in liquids and sometimes solids |
|
|
Term
| How are gas diffusion rates quantified |
|
Definition
| graham's law - diffusion of a gas is inversely proportional to the saquare root of its gram molecular weight |
|
|
Term
| what will quicken diffusion |
|
Definition
| anything that increases molecular activity therefore heating and mechanical agitation |
|
|
Term
|
Definition
|
|
Term
| "in physiology, what is the term often used to refer to pressure exerted by gases when dissolved in liquid" |
|
Definition
|
|
Term
| what does a gases tension or pressure depend on |
|
Definition
| mainly on its kinetic activity |
|
|
Term
| HOw does gravity affect gas pressure |
|
Definition
| "increases gas density, thereby increasing the rate of molecular collision and gas tension" |
|
|
Term
| what is pressure the measure of |
|
Definition
|
|
Term
| How can pressure be measured indirectly |
|
Definition
| "as the height of a column of liquid, as is commonly done to determine atmospheric pressure" |
|
|
Term
| what device is used to measure atmospheric pressure |
|
Definition
|
|
Term
| what does a barometer consist of |
|
Definition
| an evacuated glas tube appox 1 m long. its closed at the top end and the lower end is immersed in a mercury reservoir. the pressur eof the atmosphere on the mercury forces mercury u the vacuum tube a distance equivalent to the force exerted. the height of the mercury column represents the downward force of atmospheric ressure. barometer pressure is reported with readings such as 30.4 inches of mercury or 772 mm hg which means the atmospheric pressure is great enough to support a column of mercury 772 mm hg tall |
|
|
Term
|
Definition
| a term alternatively used in pressure readings and is short for torricelli - seventeenth century inventor of the mercury barometer |
|
|
Term
| what does 1 torr equal in mm hg |
|
Definition
| 1 torr is the same as 1 mm hg |
|
|
Term
| what affects a barometers mercury level besides pressure |
|
Definition
|
|
Term
| what must be corrected for accuracy in a barometer pressure reading |
|
Definition
|
|
Term
| who provides temperature correction factors for barometric pressure readings |
|
Definition
|
|
Term
| what kinds of columns are used in clinical practice |
|
Definition
| "predominantly mercury, some water columns used in low pressure situations" |
|
|
Term
| What are water and mercury columns being replaced with for the measurement of pressure |
|
Definition
| electronic and mechanical devices |
|
|
Term
| what must a mechanical or electronic device be measured against in order to be properly calibrated for pressure measurement |
|
Definition
| against a mercury or water column |
|
|
Term
| what is the simplest mechanical pressure gauge |
|
Definition
| aneroid barometer and it consists of sealed evacuated metal box with a flexible spring-supported top that responds to external pressure changes. this motion activates a geared pointerwhich provides a scale reading analogous to pressure |
|
|
Term
| what is a strain-gauge pressure transducer |
|
Definition
| "flexible chamber that can be used to measure pressure electronically. pressure changes expand and contract a flexible metal diaphragm connected to electrical sires. the physical strain on the diaphragm changes the amount of electricity flowing thourgh the wires. by measuring this change in electrical flow, we are indirectly measuring changes in pressure" |
|
|
Term
|
Definition
| the pressure exerted by a single gas in a mixture |
|
|
Term
| what does dalton's law describe with regard to the total pressure in a gas mixture |
|
Definition
| the relationship among the partial pressure and the total pressure in a gas mixture |
|
|
Term
| "If you know the percentage of a specific gas, how can total pressure be calculated?" |
|
Definition
| "if you have an amount of 21% and you know atmospheric pressure, take .21 times atmospheric pressure and that gives the total pressure" |
|
|
Term
| What do high atmospheric pressures exert in the atmosphere |
|
Definition
|
|
Term
| What are pressures above atmospheric pressure called |
|
Definition
| hyperbaric pressure - underwater diving or hyperbaric chamber |
|
|
Term
| "66 feet under water, pressure is at 2280 mmhg so what is the oxygen in an air mixure breathed by a diver?" |
|
Definition
| PO2 of .21x2280 or approx 479 mm hg which is nearly three times the PO2 at sea level |
|
|
Term
| how are hyperbaric chambers used clinically |
|
Definition
| hyperbaric chambers are used together with oxygen to treat a variety of conditions including carbon monoxide poisoning and gangrene |
|
|
Term
| can gases dissolve in liquids |
|
Definition
| "yes, i.e. carbonated water and soda" |
|
|
Term
|
Definition
| it predicts how much of a given gas will dissolve in a liquid. at a given temp the volume of a gas that dissolves in a liquid is equal to its solubility coefficient |
|
|
Term
| How does temperature affect gas solubility |
|
Definition
| high temp decreases solubility and low temp increases solubility which is why an open can of soda may still fizz if left in teh refrigerator but quickly goes flat when left at room temp |
|
|
Term
| what is temperature's effect on solubility a result of |
|
Definition
| changes in kinetic activity |
|
|
Term
| what happens to kinetic activity of any dissolved gas as a liquid is warmed |
|
Definition
| "it is increased and this increases the molecules' escaping tendency and partial pressure. as an increasing number of gas olecules escape, the amt left decreases rapidly" |
|
|
Term
| What are the three basic assumptions underlying all gas laws |
|
Definition
| "no energy is lost during molecular collisions, the volume of th eolecules themselves is negligible, no forces of mutual attractio exist between these molecules " |
|
|
Term
| what is the effect of water vapor on gas law calculations |
|
Definition
| water vapor takes up space therefore dry volume of a gas at a constant pressure and temp is always smaller than its saturated volume and the opposite is also true |
|
|
Term
| "The pressure exerted by water vapor is independent of other gases with which it mixes, depending only on the temp and RH therefore what?" |
|
Definition
| the addition of water vapor to a gas mixture always lowers the partial pressures of the other gases present |
|
|
Term
| what is the highest temperature that a substance can exist as a liquid called |
|
Definition
|
|
Term
| what is the pressure needed to maintain equilibrium between the liquid and gas phases of a substance |
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Definition
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Term
| "what together, represent the critical point of a substance" |
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Definition
| the critical temperature and critical pressure |
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Term
| What can be applied to distinguish between a true gas and a vapor |
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Definition
| concept of critical pressure |
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Term
| What concept helps explain how gases are liquified |
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Definition
| the concept of critical temperature |
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Term
| what are the two ways a gas can be liquified |
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Definition
| by cooling it to below its boiling point or cooling it to its critical temperature and then being compressed |
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Term
| Can a gas existing above its critical temperature ever be liquified by pressure alone? |
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Definition
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Term
| Can a gas with a critical temperature above ambient (as in room temperature) be liquified by pressure alone? |
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Definition
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Term
| what gases can be stored at room temp in liquid form |
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Definition
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Term
| how is liquid oxygen stored |
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Definition
| in insulated containers at temps below -183 C or 297F |
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Term
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Definition
| the bulk movement of a substance through space |
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Term
| what is the study of fluids in motion |
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Definition
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Term
| what does a static liquid's pressure depnd solely upon |
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Definition
| the depth and density of the fluid |
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Term
| what does the pressure exerted by a liquid in motion depend upon |
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Definition
| the nature of the flow itself |
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Term
| explain the pressure exerted by a static fluid on a liquid column |
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Definition
| "it is dependent only upon height of the liquid column. when the fluid flows out through the bottom tube, the pressure progressively falls all along the tube length. the decrease in pressure between each of the equally spaced vertical tubes is the same." |
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Term
| what does the second law in thermodynamics state |
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Definition
| "in any mechanbical process, there will always be a decrease in the total energy available to do work" |
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Term
| "with regard to fluid in a tube, where does frictional resistence to flow exist" |
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Definition
| within the fluid itself (viscosity) and between the fluid and the tube wall |
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Term
| "for any given tube length, flow reistance equals what" |
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Definition
| the difference in pressure between the two points along the tube divided by the actual flow |
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Term
| what are the three primary patterns of flow |
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Definition
| "laminar, turbulent, transitional" |
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Term
| "during laminar flow, how does a fluid move" |
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Definition
| discrete cylindrical layers or streamlines |
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Term
| "what is the difference pressure required to produce a given flow, under conditoins of laminar flow through a smooth tube of fixed size" |
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Definition
| defined by Poiseuille's law |
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Term
| "according to poisulle's law, for fluids flowing in a laminar pattern, what happens to the driving pressure whenever the fluid viscosity, tube length, or flow increases" |
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Definition
| driving pressure will increase |
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Term
| what happens when fluid molecules form irregular eddy currents in a chaotic pattern called what? |
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Definition
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Term
| what does the chageover from laminar to turbulent flow entail? |
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Definition
| dependent on several factors such as: fluid density (d) viscosity (h) linear velocity (v) and tube radius (r) |
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Term
| "what do viscosity, linear velocity and tube radius determine?" |
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Definition
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Term
| "in a smooth-bore tube, when does laminar flow become turbulent" |
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Definition
| when Nr exceeds 2000 (the number is dimensionless) |
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Term
| what are conditions that favor turbulent flow |
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Definition
| "increased fluid velocity, increased fluid density, increased tube radius, or decreased fluid fiscosity" |
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Term
| what law no longer applies when flow becomes turbulent |
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Definition
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Term
| what is the relationship between driving pressure and flow when flow is laminar (Poiseulle's law) |
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Definition
| the relationship is linear |
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Term
| "when flow becomes turbulent, driving pressure varies with the square of the flow. how is flow doubled under laminar conditions?" |
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Definition
| double the driving pressure |
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Term
| how is flow doubled under turbulent conditions |
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Definition
| the driving pressure would need to be indreased four-fold |
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Term
| what is transitional flow the mixture of |
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Definition
| laminar and turbulent flow |
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Term
| "when flow is mainly laminar, how is the pressure varied" |
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Definition
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Term
| "when flow is mainly turbulent, how does driving pressure vary" |
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Definition
| exponentially with the flow |
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Term
| what is the contrast of flow vs velocity |
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Definition
| flow is bulk movement of a volume of luid per unti of time (L/min or L/sec) vs. velocity as a measure of linear distance traveled by the fluid per unit of time (cm/sec) |
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Term
| what is the key factor relating velocity to flow |
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Definition
| cross-sectional area of the conducting system |
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Term
| what is the law of continuity |
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Definition
| velocity of a fluid moving through a tube at a constant flow varies inversely with the available cross-sectional area |
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Term
| What is the bernouli effect |
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Definition
| "when a fluid flows through a tube of uniform diameter, pressure decreases progressively over the tube length however when fluid passes through a constriction, pressure drop is greater. total energy at a given point in a fluid stream must be the same throughout the tube. because a moving fluids velocity and lateral pressure sum must always be equal, they must vary inversely with each other" |
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Term
| what happens when a flowing fluid encounters a very narrow passage |
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Definition
| its velocity can increase greatly |
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Term
| what happens when a flowing fluid encounters a very narrow passage that causes a rise in velocity that is so great that the fluid's lateral pressure falls below that of the atmosphere |
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Definition
| "if an open tube is placed distal to such a constriction, this negative pressure can actually pull another fluid into the primary flow stream and is called fluid entrainment" |
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Term
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Definition
| "a modified entrainment device developed by giovanni ventura and it widens just after its jet or nozzle and as long as the angle of dilation is less than 15 degrees, this widening helps restore fluid pressure back toward prejet levels" |
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Term
| what is the major drawback of a venturi tube |
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Definition
| any buildup of pressure downstream from the entrainment port decreases fluid entrainment |
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Term
| how does a pitot tube overcome the drawback of a venture tube |
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Definition
| "rather than restoring fluid pressure, a pitot tube restores fluid velocity which lessens the effect of downstream pressure on fluid entrainment" |
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Term
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Definition
| "the branch of engineering that appies hydrodynamic principles in flow circuits for purposes such as switching, pressure and flow sensing and amplification" |
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Term
| what is the coanda effect and what device uses this effect |
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Definition
| used in most fluidic circuitry. when fluid flows through a small orifice with property contoured downstream surfaces a phenomenon called wall attachment occurs |
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