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58 Cards in this Set
- Front
- Back
The transfer of heat by the direct interaction of molecules in a hot area with molecules in a cooler area
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conduction
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The worst heat conductor
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Air
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Characteristics of liquids
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1. take the shape of their containers
2. are capable of flow. 3. are difficult to compress. |
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A good clinical example of using the principle of convection to transfer heat is
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heating in infant incubators
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Heat transfer requires no direct contact between the warmer and cooler substances
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Radiation
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What decreases a patient’s loss of body heat?
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1. Increase the room temperature.
2. Move the patient away from cold windows. |
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evaporation
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1. Cools the surrounding air.
2. changes from a liquid into a gas 3. Heat energy is needed. |
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condensation
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Gas turns back into a liquid.
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Gases
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1. are easily compressible.
2. expand to fill their container. 3. are capable of flow. 4. molecular attractive forces are minimum. |
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Liquids
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1. Exert Pressure.
2. Exert a buoyant pressure. 3. Take the shape the container. 4. Are hard to compress. |
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Formula for the pressure exerted by a liquid
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liquid pressure = liquid density × liquid depth
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Pascal’s principle
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The pressure exerted by a liquid in a container depends on:
1. depth of the liquid 2. density of the liquid |
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The temperature at which condensation
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Dew Point
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Internal energy of a substance be increased by:
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1. Heating the substance
2. By performing work on it. |
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The temperature that all kinetic activity of matter cease.
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0°K
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The internal force that opposes the flow of fluids
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Viscosity
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Characteristics of Viscosity
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1. The greater the viscosity, the greater is the opposition to flow.
2. The stronger the cohesive forces, the greater the viscosity. 3. Fluid viscosity is equivalent to friction between solids. |
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Liquid that has the lowest surface tension
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Alcohol
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A liquid in a small tube tends to move upward against the force of gravity
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capillary action
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Heat transfer in both liquids(Fluids) and gases occurs mainly
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Convection
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Clinical examples of the principle of capillary action
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1. Blood samples
2. absorbent humidifier wicks 3. certain surgical dressings |
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Temperature that vapor pressure of a liquid equals the pressure exerted on the liquid by the surrounding atmosphere
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Boiling point
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Characteristics of Boiling
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1. A liquid’s boiling point varies with the atmospheric pressure
2. Boiling a liquid requires more energy than does evaporating it. 3. The greater the ambient pressure, the lower is the boiling point. |
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Can change into a gas at temperatures lower than its boiling point through a process called
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evaporation
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Characteristic of Water Vapor
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1. Exerts pressure.
2. Exhibits kinetic activity. |
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When a gas holds all the water vapor molecules
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Saturation
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Methods to increase the rate of evaporation of a container of water
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1. Increase the temperature of the surrounding air.
2. Decrease the pressure of the surrounding air. 3. Increase the temperature of the water. |
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The kinetic activity of water vapor molecules
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Water vapor pressure
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The term for the actual content or weight of water present in a given volume of air
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Absolute humidity
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The absolute humidity(water vapor content) of saturated gas at normal body temperature (37°C)
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43.8 mg/L or 44 mg/L
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The water vapor pressure of saturated gas at normal body temperature (37°C)
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47.0 mm Hg
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What occurs during the evaporation?
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The air is cooled.
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When the water vapor content of a volume of gas equals its capacity
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The RH is 100%
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When the temperature of a saturated gas drops down to its dew point
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Excess water vapor will condense as visible droplets
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Forms of vaporization
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Both boiling and evaporation are forms of vaporization.
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Contrast between Gases & Liquids
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Unlike liquids, gases are readily compressed and expanded and fill the spaces available to them by diffusion.
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As a gas is warmed or temperature of gas rises:
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1. kinetic activity increases.
2. its molecular collisions increase. 3. its pressure rises. |
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Avogadro’s law
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states that the 1-g atomic weight of any substance contains exactly the same number of atoms, molecules, or ions.
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Diffusion
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the process whereby molecules move from areas of high concentration to areas of lower concentration.
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Formula for Pressure
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force ÷ unit area
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One atmosphere (1 atm) of pressure is the same as:
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1. 760.0 mm Hg
2. 29.9 inches Hg 3. 1034.0 g/cm2 4. 14.7 lb/in2 |
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Factors that a gas can dissolve in a liquid
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1. solubility coefficient of the gas
2. temperature of the liquid 3. gas pressure above the liquid |
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What occurs when a gas expands
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Molecular collisions decrease.
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When a gas decreases pressure
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the volume will increase.
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What occurs when water vapor is added to a dry gas at a constant pressure?
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1. The volume occupied by the gas mixture increases.
2. The relative humidity of the mixture increases. 3. The partial pressure of the original gas is reduced. |
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The temperature that Liquid is heated is called
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critical temperature
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Characteristics of Oxygen
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1. No pressure can keep it in a liquid state above –118.8°C.
2. Its critical temperature is above normal room temperature. 3. It cannot be turned into a liquid at room temperature. |
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Solids maintain their shape because their atoms are kept in place by strong mutual attractive forces
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van der Waals forces
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Gases that have critical temperatures above normal room temperature
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1. CO2 (carbon dioxide)
2. N2O (nitrous oxide) |
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Liquid oxygen is produced by separating it from a liquefied air mixture at a temperature below its boiling point, which is:
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–183°C
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Formula for the resistance to flow of a fluid through a
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resistance = pressure ÷ flow
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A fluid moves in discrete cylindrical streamlines
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Laminar
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What happens to a fluid if the cross-sectional area of the tube in which it flows decreases
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Its velocity will decrease.
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turbulent flow
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proportional to the square of the flow
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Bernoulli’s principle
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Lateral pressure will fall
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The most common application of fluid entrainment is (in Bernoulli’s principle)
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air injector
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Characteristics of sublimation
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1. going directly from solid to vapor form
2. never becoming a liquid 3. skipping the melting phase |
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Purposes of use of a Venturi tube
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1. to restore fluid pressure distal to a restricted orifice
2. to help keep entrainment ratios constant with varying flows 3. to make possible entrainment of large volumes of gas |