CLO 3 & 4 Study Guide PDF

CLO 3, 4 STUDY GUIDE CLO 3: Describe change of physical states of matter 3.1 Define potential energy, absolute zero, and temperature scale conversions 3.2 Discuss factors contributing to melting, freezing, viscosity, cohesion and adhesion, surface tension, and capillary action 3.3 Define terms and p...

CLO 3, 4 STUDY GUIDE CLO 3: Describe change of physical states of matter 3.1 Define potential energy, absolute zero, and temperature scale conversions 3.2 Discuss factors contributing to melting, freezing, viscosity, cohesion and adhesion, surface tension, and capillary action 3.3 Define terms and principles related to boiling, evaporation, vapor pressure, dew point, and humidity CLO 4: Explain gas behavior under changing conditions 4.1 Compute calculations related to relative humidity, body humidity, absolute humidity, and humidity deficit 4.2 Define calculations related to Dalton’s Law, Boyle’s Law, Charles’s Law, Gay-Lussac’s Law, and the combined gas laws 4.3 Define ATPS, BTPS, and STPD conversions 4.4 Discuss the critical temperature and critical pressure of selected gases including oxygen, carbon dioxide, and helium 4.5 Discuss laminar and turbulent flow, Bernoulli Effect, Venturi Principle, and the Coanda Effect 4.6 Describe the physics of electrical current, resistance, voltage, wattage, and the Ohm 3.1 Define potential energy, absolute zero, and temperature scale conversions Potential energy is referred to as the energy of position—that is, the energy possessed by an object balanced on a shelf. Potential energy is a result of the strong attractive forces between molecules. These intermolecular forces are why solids are rigid and liquids have viscosity and cohesiveness. These same intermolecular forces are not as strong in gases. Kinetic energy is the energy of motion, such as that of a falling object. Most internal energy in gases is in the form of kinetic energy Absolute zero: In concept, absolute zero is the lowest possible temperature that can be achieved. That is the temperature at which there is no kinetic energy. Because there is no energy, the molecules cease to vibrate and the object has no heat that can be measured Temperature scale conversions: Celsius to Fahrenheit F=(01.8XC) + 32 Fahrenheit to Celsius C=(F-32)/ 1.8 Celsius to kelvin C + 273 Kelvin to Celsius K – 273 3.2 Discuss factors contributing to melting, freezing, viscosity, cohesion and adhesion, surface tension, and capillary action Liquid-Solid Phase Changes (Melting and Freezing) Melting: When a solid is heated, its molecular kinetic energy increases. This added internal energy increases molecular vibrations. If enough heat is applied, these vibrations eventually weaken the intermolecular attractive forces. At some point molecules break free of their rigid structure and the solid changes into a liquid Freezing is the opposite of melting. Because melting requires large amounts of externally applied energy, you would expect freezing to return this energy to the surroundings, and this is exactly what occurs. During freezing, heat energy is transferred from a liquid back to the environment, usually by exposure to cold. As the kinetic energy of a substance decreases, its molecules begin to regain the stable structure of a solid. According to the first law of thermodynamics, 4 the energy required to freeze a substance must equal that needed to melt it. The freezing and melting points of a substance are the same. Viscosity is the force opposing a fluid's flow and is similar to friction in solids. The viscosity of a fluid is directly proportional to the cohesive forces between its molecules. The stronger these cohesive forces are, the greater the fluid's viscosity. The greater a fluid's viscosity, the greater its resistance to deformation and the greater its opposition to flow. Cohesion and AdhesionThe attractive force between like molecules is called cohesion. The attractive force between unlike molecules is called adhesion. Cohesion= convex Adhesion= concave Surface tension is a force exerted by like molecules at the surface of a liquid The inward forces affect molecules on the surface This imbalance in forces causes the surface film to contract into the smallest possible surface area, usually a sphere or curve (meniscus) This is why a water droplet is a spherical shape Capillary action is a phenomenon in which a liquid in small tube moves upward against gravity. It has both adhesive and surface tension forces. The capillary action is the basis for blood samples obtained by use of a capillary tube. The absorbent wicks used in some gas humidifiers are also an application of this principle as well as some surgical dressings. 3.3 Define terms and principles related to boiling, evaporation, vapor pressure, dew point, and humidity Liquid-Vapor Phase Changes Only after ice completely melts does additional heat increase the temperature of the newly formed liquid. As the water temperature reaches 100°C, a new change of state begins—from liquid to vapor. This change of state is called vaporization. There are two different forms of vaporization: boiling and evaporation. The boiling point of a liquid is the temperature at which its vapor pressure exceeds atmospheric pressure. When a liquid boils, its molecules must have enough kinetic energy to force themselves into the atmosphere against the opposing pressure. Evaporation, Vapor Pressure, and Humidity Boiling is only one type of vaporization. A liquid can also change into a gas at temperatures lower than its boiling point through a process called evaporation. Water is a good example. When at a temperature lower than its boiling point, water enters the atmosphere via 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 molecules near the surface to escape into the surrounding air as water vapor After water is converted to a vapor, it acts like any gas. Not to be confused with visible particulate water, such as mist or fog, this invisible gaseous form of water is called molecular water. Molecular water obeys the same physical principles as other gases and exerts a pressure called water vapor pressure. This pressure needs to be considered when gas exchange is being calculated. Evaporation requires heat. The heat energy required for evaporation comes from the air next to the water surface. As the surrounding air loses heat energy, it cools. This is the principle of evaporative cooling, which was previously described. CLO 4 4.1 Compute calculations related to relative humidity, body humidity, absolute humidity, and humidity deficit relative humidity: RH formula RH= content (AH) absolute humidity/saturated capacity x 100 (rule of thumb: small number divided by the big number times 100) The humidity deficit is associated with a BH (Body Humidity) of less than 100% and represents the amount of water vapor the body must add to the inspired gas to achieve saturation at body temperature (37°C). To compute the humidity deficit, simply subtract the actual water vapor content from its capacity at 37°C (43.8 mg/L). The BH formula is the same as RH except that the capacity (or denominator) is fixed at 43.8 mg/L: BH= content mg/L / 43.8x 100 4.2 Define calculations related to Dalton’s Law, Boyle’s Law, Charles’s Law, Gay-Lussac’s Law, and the combined gas laws Partial Pressures (the Dalton's Law) describes the relationship between the partial pressure and the total pressure in a gas mixture. Oxygen making up 21% of the mixture of the atmosphere would exert 21% of the total pressure. Assuming a normal atmospheric pressure of 760 torr, the individual partial pressure is computed as follows: PO2 = 0.21X760 torr =160 torr. The Boyle's law states that with constant temperature, the volume and pressure are indirectly proportional. That is, as the pressure is increased, the volume will decrease. P1xV1=P2xV2 The Boyle's law is used in pulmonary function labs that perform body plethysmography (pulmonary function test) ex. The lungs The Charles law states that with pressure constant, the volume of a gas is directly proportional to its temperature. A warm gas will take up more volume than a cooler gas at the same pressure. This effect can be seen with mechanical ventilators. Mrs Gibbys example was a hot air balloon. V1/T1=V2/T2 The Gay-Lussac's law assumes that gas volume is constant and pressure and temperature are directly proportional to one another. P1/T1=P2/T2. Mrs gibbys example was a hair spray bottle. Combined gas laws: p1v1/t1=p2v2/t2 4.3 Define ATPS, BTPS, and STPD conversions ATPD, Ambient temperature and pressure dry; ATPS, Ambient temperature and pressure saturated; BTPS, body temperature and pressure saturated; STPD, standard temperature (0.0°C) and pressure (760 mm Hg) dry. In gas volume conversions, the four most common computations are as follows ATPD to BTPS, ATPS to BTPS, ATPS to STPD, and STPD to BTPS. These are also known as correction factors. Correction factors can be used to convert gas volumes from one set of conditions to another. Such computations are common in pulmonary function laboratories and are also common to mechanical ventilators. For example, suppose you set a tidal volume on a ventilator to 500 mL. If the ventilator's output control valve metered out 500 mL and the gas was heated and humidified to body conditions (fully saturated at 37°C), then the gas volume would increase because of the heat and addition of water vapor. But how much would it increase? 4.4 Discuss the critical temperature and critical pressure of selected gases including oxygen, carbon dioxide, and helium For every liquid, there is a temperature above which the kinetic activity of its molecules is so great that the attractive forces cannot keep them in a liquid state. This temperature is called the critical temperature. The critical temperature is the highest temperature at which a substance can exist as a liquid. The pressure needed to maintain equilibrium between the liquid and gas phases of a substance at this critical temperature is the critical pressure. Together, the critical temperature and pressure represent the critical point of a substance. Critical Temperature Points of Three Gases Helium (He) - -267.9 Celsius and – 450.2 Fahrenheit Oxygen (O2) -118.8 Celsius and -181.1 Fahrenheit Carbon dioxide C02 31.1 Celsius and 87.9 Fahrenheit 4.5 Discuss laminar and turbulent flow, Bernoulli Effect, Venturi Principle, and the Coanda Effect Laminar Flow: during laminar flow, a fluid moves in discrete cylindrical layers or streamlines (moves in a strait line) Turbulent Flow: Under certain conditions the pattern of flow through a tube changes significantly, with a loss of regular streamlines. Instead, fluid molecules form irregular eddy currents in a chaotic pattern called turbulent flow (Key words: chaotic pattern) Depends on fluid density, viscosity, linear velocity, and tube radius When flow is turbulent, Poiseuille’s law no longer applies, the pressures will increase Bernoulli Principle: Bernoulli principle states that as the flow increases, the pressure in the fluid will decrease along with its potential energy. (Mrs gibbys example was placing your thumb into the opening of a hose to increase the pressure) Also think Venturi effect. A special application of the Bernoulli principle is the Venturi effect. The Venturi effect describes the flow of a gas through a constriction and the subsequent drop in pressure at the constriction. As the gas passes from a larger bore through a constriction, the flow increases and the pressure perpendicular to the constriction decreases. The Venturi effect can be used for measuring gas flow in ventilators. Fluid Entrainment (Assosciated with the Venturi effect) Jet entrainment is the design principle used in simple O2 masks with variable FiO2 settings, although they are often mistakenly called Venturi masks. In this case, a pressurized gas, usually O2, serves as the primary flow source The primary principle underlying most fluidic circuitry is a phenomenon called wall attachment, or the Coanda effect. This effect is observed mainly when a fluid flows through a small orifice with properly contoured downstream surfaces. 4.6 Describe the physics of electrical current, resistance, voltage, wattage, and the Ohm Electricity moves from point A to point B because of differences in voltage. Voltage is the power potential behind the electrical energy. Low-voltage batteries (e.g., 9 Volt) are sufficient to power a small flashlight but inadequate to power a major appliance such as a microwave oven. Chapter 3 page 36-37 of Egans explains the physics of electrical current and all the variables she wants us to know about for the CLO.