1 / 30

Chapter 12

Chapter 12. The Gas Laws. Inverse Relationship. Direct Relationship. PRESSURE AND VOLUME RELATIONSHIP. In book - page 330. howstuffworks. Boyle’s Law. Boyle’s Law is Pressure/Volume relationship. FORMULA V 1 P 1 =V 2 P 2. 25 cm 3 at 75 psi changes to 20 cm 3 at what new pressure?

bonnie
Download Presentation

Chapter 12

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Chapter 12 The Gas Laws

  2. Inverse Relationship

  3. Direct Relationship

  4. PRESSURE AND VOLUME RELATIONSHIP In book - page 330 howstuffworks

  5. Boyle’s Law

  6. Boyle’s Law is Pressure/Volume relationship FORMULA V1P1=V2P2 25 cm3 at 75 psi changes to 20 cm3 at what new pressure? 200 mls. @100 kpa will occupy what volume at 60 kpa (kilopascals) As Pressure increases the volume of a gas decreases…inverse relationship

  7. Boyles Law • Pressure1 x Volume1 = Pressure2 x Volume2 • For a given mass of gas at a constant temperature the volume of the gas varies inversely with the pressure. • In an inverse relationship the product of the two variable quantities is constant.

  8. Deep sea diving: Boyle’s Law Nitrous Oxide forms in the body when breathing high-pressured air The Bends: is when ascending out of water and nitrogen is diffusing out of the blood. Bubbles form. Breathing Inhaling, the diaphragm goes downward. Lungs are area of low pressure allowing air to come in. Exhaling, diaphragm goes upward.High pressure in lungs, air goes out. Examples The Bends Web Site = http://science.howstuffworks.com/question101.htm

  9. http://science.howstuffworks.com/lung1.htm

  10. Diseases or Conditions that influence the machanics of breathing • Asthma: The bronchioles constrict, reducing the size of the airways. This cuts down on the flow of air and makes the respiratory muscles work harder. • Emphysema: The lungs become stiff with fibers and become less elastic, which increases the work of the respiratory muscles. • Bronchitis: The airways become inflamed and narrower, which restricts the flow of air and increases the work of the respiratory muscles • Pneumothorax: Air in the chest cavity equalizes the pressure in the chest cavity with the outside air and causes the lungs to collapse. This is usually caused by trauma or injury. Apnea: Breathing slows or stops under a variety of conditions. There are many types of apnea, and they are usually caused by problems in the respiratory centers of the brain.

  11. Gases diffusing in lungs

  12. Charles’s Law

  13. Charles Law • Volume1 =Volume2 Temperature1 Temperature2 • The volume of a fixed mass of gas is directly proportional to its Kelvin temperature if the pressure is kept constant. • In a direct relationship the ratio of the two quantities that change is constant.

  14. Charles’ law Calculations • 200 mls. Of a gas is at 1000C. The temp changes to 1500C, find the new Volume. • 100 mls. Of a gas is at 1500C and the new volume changes to 75 mls. What is the new Temperature (in Kelvin)?

  15. Hot Air Balloons http://travel.howstuffworks.com/hot-air-balloon2.htm

  16. How Migrating Animals Take Advantage of Thermals and UpdraftsBirds, butterflies and dragonflies all take advantage of rising currents to migrate. Think about the shape of a soaring eagle, crane, hummingbird, and monarch butterfly. All these animals are so light for their large wings that even gently rising air can push them up when their wings are spread. Cumulous clouds are tell-tale signs of thermals A thermal is a column of rising air, caused by uneven heating of the earth Thermals and Migration

  17. Thermal Bubbles

  18. Temperature and Volume Law Charles’s law states That the volume of a Fixed mass of gas is Directly porportional To its Kelvin temp. if The pressure is kept Constant. As temperature increases volume increases as well

  19. Hot air balloon: Charles’s Law As the heat source increases the volume of the balloon increases allowing it to become less dense and rise. Thermals: Charles’s Law Hot air pockets which have increased volume when heated which decrease their density. Therefore the hot air can rise. Thermals condense over the ocean causing cool wind to form new thermals. Birds use them and hot air balloons don’t like them. Examples

  20. Cars and Gas Lawshttp://auto.howstuffworks.com/engine3.htm

  21. Gay-Lussac’s Law • The pressure of a gas is directly proportional to the Kelvin temperature if the volume remains constant. P1=P2 T1 T2

  22. Combined Gas Law • P1 x V1= P2 x V2 T1 T2 • Pressure times Volume divided by temperature  the new pressure times volume divided by temperature

  23. Boyle’s Law Problem> SOLVE! V1 = 25 mL. P1 = 100 kPa P2 = 125 kPa V2 = X (variable) 25(100) = X(125) 2500 = 125X 20 = X Charles’ Law Problem > SOLVE! (Convert all temps. To Kelvin) V1 = 200 mLs T1 = 30o C. = 303o K V2 = X T2 = 100o C =373o K 200/303=X/373 74600=303X X=246mls

  24. Combined gas law- V1=150ml P1=101.3kpa T1=2730K V2=300ml P2=X T2=3230K (150)(101.3)/323=(300)(X)/273 X= 60 kpa

  25. Daltons Law • The total pressure exerted by a mixture of gases is equal to the sum of the partial pressure of the component gases. • Ptotal = PA + PB + PC…. • Problem: Find the partial pressure of Nitrogen, Oxygen, other gases in the room…use today’s barometer reading.

  26. Mt. Everest • Physiology on Mt. Everest • 10.67 kPa of O2 needed by humans • Pressure on summit: 1/3 STP

  27. gas masks Pilots and mountaineers must have supplemental oxygen when they are working in high altitudes, where oxygen is scarce.

  28. Grahams Law • The rate of effusion of a gas is inversely proportional to the square route of the gas’s molar mass. This relationship is also true for the diffusion of gasses.

  29. Graham’s Law: The diffusion rate of 2 gases is inversely Proportional to the square route of the molecular gases. • Compare gas A to gas B • Rate of diffusion Gas A = square route Gas B Mass • Gas B Gas A Mass • Smaller masses diffuse faster • To solve: Put larger mass on top, the answer = how many times faster the smaller gas diffuses. • Example: Hydrogen diffuses 4.36 times faster • than fluorine.

  30. Ideal Gas Law: R = PV Tn Which is: Ideal Gas Constant = Pressure x Volume Temperature x Moles

More Related