lect7_16Sept08

Lect7_16Sept08 - First TEST CHAPTERS 1 5 Tuesday 23 September HELP SESSION Sunday 21 September 5:00 6:45 PM Heldenfels 100 Do Not Forget CAPA

Info iconThis preview shows pages 1–4. Sign up to view the full content.

View Full Document Right Arrow Icon
1 First TEST CHAPTERS 1 – 5 Tuesday 23, September Do Not Forget CAPA ASSIGNMENTS CAPA 4 BEING DISTRIBUTED HELP SESSION, Sunday 21 September 5:00 –6:45 PM Heldenfels 100 GASES AND KINETIC-MOLECULAR THEORY Suggested Textbook Problems - CHAPTER 5 READ CHAPTER 5 13, 19, 25, 29, 33, 35, 43, 47, 52, 55, 59, 65, 68, 73, 77, 85, 87 The Gas Laws Solids Liquids • Gas - a substance that is characterized by widely separated molecules in rapid motion • Mixtures of gases are uniform. Gases will expand to fill containers Gases Three States of Matter Three States of Matter Examples of Gaseous Substances • Common gases O 2 and N 2 , the major components of "air" • Other gases H 2 F 2 , Cl 2 , gaseous diatomic molecules; •H 2 and He are the ‘lighter than air’ gases
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
2 Gases and Vapors • What is the difference between a gas and a vapor? – Gases normally in the gaseous state at 25°C and 1 atm pressure – A vapor is the gaseous form of any substance that is normally in the liquid or solid state at normal temperatures and pressures The Gas Laws • Early experiments found that four variables were sufficient to fully describe the state of a gas Pressure (P) Volume (V) Temperature (T) The amount of the gas in moles (n) • Gas pressure results from collisions of gas molecules with the container walls. • Pressure depends on the number of collisions per unit time AND- how hard the gas molecules strike the container wall! Pressure • Pressure is the force per unit area which a Pressure is the force per unit area which a gas exerts • on the walls of the container A F P = The SI unit of pressure is the Pascal 1 Pa = 1 Newton /m 2 = 1 kg m s 2 Composition of the Atmosphere Gas % by Volume N 2 78.09 O 2 20.94 Ar 0.93 CO 2 0.03 He, Ne, Kr, Xe 0.002 CH 4 0.00015 H 2 0.00005 Composition of Dry Air Gravity exerts a force on the earth ’s atmosphere s atmosphere A column of air 1 m 2 in cross section exerts a force of 1.01325 x 10 exerts a force of 1.01325 x 10 5 N. N. The pressure of a 1 m The pressure of a 1 m 2 column of air column of air is 1.01325 x 10 is 1.01325 x 10 5 Pa. Pa. Atmospheric Pressure Atmospheric Pressure 14.70 lbs/ in 2 Also 760 mm Hg Or 760 Torr
Background image of page 2
3 Hg density = 13.6 g/mL CAN WE MAKE A WATER BAROMETER? Vacuum YES •Bu t • Density of water = 1.00 grams/cm 3 Therefore Height of Column is = (13.6/1) x 76.0 cm = 1.03 x 10 3 cm or 33.9 feet What practical implications does this have for simple hand operated water pumps? The Definition of an Ideal Gas • Ideal gases - molecules have negligible intermolecular attractive forces –Occupy a negligible volume compared to the container volume http://intro.chem.okstate.edu/1314F00/Laboratory/GLP.htm http://phet.colorado.edu/simulations/sims.php?sim=Gas_Properties Boyle's Law – The pressure - volume relationship • The volume occupied by the gas is
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Image of page 4
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 09/26/2008 for the course CHEM 107 taught by Professor Generalchemforeng during the Fall '07 term at Texas A&M.

Page1 / 8

Lect7_16Sept08 - First TEST CHAPTERS 1 5 Tuesday 23 September HELP SESSION Sunday 21 September 5:00 6:45 PM Heldenfels 100 Do Not Forget CAPA

This preview shows document pages 1 - 4. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online