Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Main AR Standards

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu AR STANDARDS for ch

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Table of Contents Chapter 11 Gases Section 4 Diffusion and Effusion

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Objectives Describe the process of diffusion. State Graham’s law of effusion. State the relationship between the average molecular velocities of two gases and their molar masses. Chapter 11 Section 4 Diffusion and Effusion

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Opener #20 - Wednesday, December 12, 2012 Pick up calculator & study guide questions. Have out notes packet. Be sure you have turned in computer simulation lab AND yesterday’s pressure probe Boyle’s Law Lab. 1. A sample of a gas occupies 250. mL at 1.00 atm of pressure. If the pressure increases to 2.00 atm while the temperature stays the same,what is the new volume? 2. An engineer pumps 5.00 mol of carbon monoxide gas into a cylinder that has a capacity of 20.0 L. What is the pressure in kPa of CO inside the cylinder at 25°C? 3. Ammonia can react with oxygen to produce nitrogen and water according to the following equation. 4NH 3 (g) + 3O 2 (g) --> 2N 2 (g) + 6H 2 O(l) If 1.78 L of O 2 reacts, what volume of nitrogen will be produced? Assume that temperature and pressure remain constant.

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Assignments WED DEC 12 CW: Notes discussed together first. CW: ch Study Guide Questions HW: Final Exam Study Guide due Wed. Dec. 19th Be sure you have turned in your 2 labs with ALL questions answered from simulation lab and pressure probe lab. Make sure all of your notes are completed including problems. TEST ch is FRIDAY.

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Diffusion and Effusion The constant motion of gas molecules causes them to spread out to fill any container they are in. The gradual mixing of two or more gases due to their spontaneous, random motion is known as diffusion. Effusion is the process whereby the molecules of a gas confined in a container randomly pass through a tiny opening in the container. Chapter 11 Section 4 Diffusion and Effusion

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Visual Concepts Click below to watch the Visual Concept. Visual Concept Comparing Diffusion and Effusion - skip Chapter 11 t/ch11/sec04/vc00/hc611_04_v00fs.htm

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Graham’s Law of Effusion Rates of effusion and diffusion depend on the relative velocities of gas molecules. The velocity of a gas varies inversely with the square root of its molar mass. Recall that the average kinetic energy of the molecules in any gas depends only the temperature and equals. Chapter 11 Section 4 Diffusion and Effusion For two different gases, A and B, at the same temperature, the following relationship is true.

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Graham’s Law of Effusion From the equation relating the kinetic energy of two different gases at the same conditions, one can derive an equation relating the rates of effuses of two gases with their molecular mass: Chapter 11 Section 4 Diffusion and Effusion This equation is known as Graham’s law of effusion, which states that the rates of effusion of gases at the same temperature and pressure are inversely proportional to the square roots of their molar masses.

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Visual Concepts Click below to watch the Visual Concept. Visual Concept Graham’s Law of Effusion - show Chapter 11 ent/ch11/sec04/vc01/hc611_04_v01fs.htm

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Visual Concepts Click below to watch the Visual Concept. Visual Concept Equation for Graham’s Law of Effusion - skip Chapter 11 x/student/ch11/sec04/vc02/hc611_04_ v02fs.htm

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Graham’s Law Section 4 Diffusion and Effusion Chapter 11

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Graham’s Law of Effusion, continued Sample Problem J Compare the rates of effusion of hydrogen and oxygen at the same temperature and pressure. Chapter 11 Section 4 Diffusion and Effusion

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Sample Problem J Solution Given: identities of two gases, H 2 and O 2 Unknown: relative rates of effusion Solution: The ratio of the rates of effusion of two gases at the same temperature and pressure can be found from Graham’s law. Chapter 11 Graham’s Law of Effusion, continued Section 4 Diffusion and Effusion

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Sample Problem J Solution, continued Substitute the given values into the equation: Hydrogen effuses 3.98 times faster than oxygen. Chapter 11 Graham’s Law of Effusion, continued Section 4 Diffusion and Effusion

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Practice Problems pg. 388 #1-3 Complete practice problems #1-3 pg Show work. v

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu ANSWERS Practice Problems pg. 388 #1-3 Complete practice problems #1-3 pg Show work. v

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Note to self - additional stoichiometry & ideal gas problem with acetylene gas C2H2 etc. See also worksheets, etc.

© Copyright Pearson Prentice Hall Slide of 25 End Show SECTION PROBLEMS Explore these interactive demonstrations to learn how to use equations to solve science problems. Section 4: Diffusion and Effusion Stoichiometry of gases Volume–Volume Calculations Stoichiometry of Gases Rates of Effusion

© Copyright Pearson Prentice Hall Slide of 25 End Show HIGHLIGHTS OF 11.4

© Copyright Pearson Prentice Hall Slide of 25 End Show Online Self-Check Quiz Complete the online Quiz and record answers. Ask if you have any questions about your answers. click here for online Quiz 11.4 (7 questions) You must be in the “Play mode” for the slideshow for hyperlink to work.

© Copyright Pearson Prentice Hall Slide of 28 End Show VIDEOS FOR ADDITIONAL INSTRUCTION Additional Videos for Section 11.4: Diffusion and Effusion Graham's Law

© Copyright Pearson Prentice Hall Slide of 28 End Show SCI LINKS FOR CHAPTER Additional Student SCI LINKS for CHAPTER 11 The NSTA-sponsored SciLinks Web site contains links to accurate and up- to-date science information on the Internet. Just click on the button below to go to the SciLinks site at and log in. Then, type in the SciLinks code for the topic you want to research. The following is a list of the SciLinks codes for this chapter. Chapter 11: Gases Topic: Gases SciLinks code: HC60638 Topic: Gas Laws SciLinks code: HC60637 Topic: Torricelli SciLinks code: HC61539 Topic: Robert Boyle SciLinks code: HC61317 Topic: Avogadro’s Law SciLinks code: HC60131 Topic: Thomas Graham SciLinks code: HC61517

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu End of Chapter 11.4 Show