Boyles law (compresion) (relation between pressure & volume)

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this report made by koya university students of chemical engineering (shwan sarwan &aree salah).

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Boyles law (compresion) (relation between pressure & volume)

  1. 1. Koya University Faulty of Engineering School of Petroleum & Chemical Engineering Chemical Engineering department EXPERIMENT NUMBER TWO BOYLES LOW Thermodynamics Boyle's low Instructor: Mr.Rebwar & Mr.Omer Author Name: Aree Salah Tahir & shwan sarwan sadiq Experiment Contacted on: 29/oct/2013 Report Submitted on: 12/nov /2013
  2. 2. List of content: Abstract ……………………………………. Objectives…………………………………... Introduction ………………………………… Background Theory ………………………... Method ……………………………………... Calculation………………………………….. Equipment and components used…………… Discussion …………………………………... References …………………………………...
  3. 3. Abstract: Pressure and volume are inversely proportional to Each other. This means that as the pressure Decreases, the volume increases, and as the pressure Increases, the volume decreases. One way to think Of this is if you push on a gas by decreasing its Volume, it pushes back by increasing its pressure. This relationship is called Boyle’s Law and makes up Part of the ideal gas law.
  4. 4. OBJECTIVES: The purpose of Boyle's law is to set up a relationship between the pressure and the volume of a gas. The law states that as the pressure of a gas increases, its volume decreases, and vice-versa. References…(1)
  5. 5. Introduction: Boyle's Law explains how the volume of a gas varies with the surrounding pressure. Many aspects of scuba diving physics become clear once you understand this simple gas law. Boyle's Law is: PV = c In this equation, “P” represents pressure, “V” signifies volume and “c” represents a constant (fixed) number. If you are not a math person, this may sound really confusing – don't despair! This equation simply states that for a given gas (such as air in a scuba diver's buoyancy compensator), if you multiply the pressure surrounding a gas by the volume of gas you will always end up with the same number. Because the answer to the equation can not change (that's why it is called a constant), we know that if we increase the pressure surrounding a gas (P), the volume of the gas (V) must get smaller. Conversely, if we decrease the pressure surrounding a gas, the
  6. 6. volume of the gas will become greater. That's it! That's Boyle's entire law. Almost. The only other aspect of Boyle's Law that you need to know is that the law only applies at a constant temperature. If you increase or decrease the temperature of a gas, the equation doesn't work anymore. References…(2)
  7. 7. BACKGROUND THEORY: When the volume of a gas shrinks, the gas molecules have less space to move around and so they hit their container more often. The more frequently the gas impacts the container walls, the higher the pressure. So, as volume decreases, the pressure increases. If the container expands, the impacts are less frequent and the pressure decreases. This relationship can be described using mathematics as well. Mathematically, Boyle’s Law states that PV = k where k is any constant. Boyle’s Law is important for both astronauts and divers. Since the pressure in space is near zero, space suits have to be able to withstand the expansion of the air that is within the suit when the astronaut goes outside. When divers are surfacing, they must exhale. If they don’t, the air that is held in their lungs will expand and could rupture the lung tissue.
  8. 8. This experiment shows how the volume of the air in whipped cream reacts to lowering pressure. References…(3)
  9. 9. Method: switch on unit master switch (4) open the air discharge valve (1) on the lid of the cylinder place both 3-way valves (3) in position 2 switch on compressor using switch until the liquid level has reached the lowest mark (2) on the scale on the vessel. switch off compressor close discharge valve on the lid of the cylinder! start data acquisition program and make the corresponding settings switch on compressor at the latest at liter residual volume for the air enclosed ,switch off the compressor open graph measured valued and interpret leave pressure cylinder uncharged and continue immediately with the compression experiment
  10. 10. EQUIPMENT and COMPONENTS USED: (1) Tank 1 for isothermal change of state, (2) Digital displays, (3) 5/2-way valve for switching between compression and expansion, (4) Heating controller, (5) Digital display, (6) Tank 2 for isochoric change of state References…(4)
  11. 11. Discussion: How Does Boyle's Law Apply to Scuba Diving?: Boyle's Law effects almost every aspect of scuba diving because it describes the role of water pressure in the dive environment. As a diver descends, the water pressure around him increases, causing air in his scuba equipment and body to occupy a smaller volume (compress). As he ascends, water pressure decreases, so Boyle's Law states that the air in his gear and body expand to occupy a greater volume. Many of the safety rules and protocols in scuba diving were created to help a diver compensate for the compression and expansion of air due to changes in water pressure. Why does the pressure of a gas increase when the volume of the container decreases? Remember that the pressure of a gas on the walls of the container is due to the collisions of the molecules on the walls of the container. The change in momentum of these molecules in unit time is a force exerted by the walls of the vessel on the molecules, which, by Newton's third law, exert an equal and opposite force on the walls of the vessel. This force, divided by the area of the walls in contact with the gas, is the pressure of the gas.
  12. 12. Why Is a Constant Temperature Necessary to Use Boyle's Law?: As mentioned above, Boyle's Law only applies to gases at a constant temperature. Heating a gas causes it to expand, and cooling a gas causes it to compress. A diver can witness this phenomenon in action when he submerges a warm scuba tank in cooler water. The pressure gauge reading of a warm tank will drop when the tank is submerged in cool water as the gas inside the tank compresses. What happens to an ideal gas in an infinite space when the pressure is 0? Does the gas expand to infinite volume? Pressure will never be 0 in an infinite volume hypothetical scenario because you have introduced a gas. Regardless of how little you have added, there will always be that finite and measurable amount of gas in an infinite space. As volume increases, the pressure and temperature will decrease. Subsequently, you should expect the pressure to approach but never reach absolute 0, and you should expect the temperate to approach but never reach absolute 0
  13. 13. References: 1: http://www.chm.davidson.edu/vce/gaslaws/boyleslaw. html 2: http://scuba.about.com/od/Theory/p/Boyles-Law-AndScuba-Diving.htm 3: http://littleshop.physics.colostate.edu/activities/atmos2 /PressureVolumeRelated 4: http://www.gunt.de/static/s3438_1.php

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