ch05_lecture_6e_final-1 (1).ppt - General Chemistry I(Fall...

This preview shows page 1 - 17 out of 75 pages.

5-1General Chemistry I (Fall 2017, UF CHM 2045)Instructor:Dr. Simon E. LopezAdjunct LecturerChapter 5 Slides
5-2Chapter 5Gases and the Kinetic-Molecular Theory
5-3Gases and the Kinetic Molecular Theory5.1 An Overview of the Physical States of Matter5.2 Gas Pressure and Its Measurement5.3 The Gas Laws and Their Experimental Foundations5.4 Rearrangements of the Ideal Gas Law5.5 The Kinetic-Molecular Theory: A Model for Gas Behavior5.6 Real Gases: Deviations from Ideal Behavior
5-4Distinguishing gases from liquids and solids.An Overview of the Physical States of MatterGas volume changes significantly with pressure.Solid and liquid volumes are not greatly affected by pressure.Gas volume changes significantly with temperature.Gases expand when heated and shrink when cooled. The volume change is 50 to 100 times greater for gases than for liquids and solids.Gases flow very freely.Gases have relatively low densities.Gases form a solution in any proportions.Gases are freely miscible with each other.
5-5Figure 5.1The three states of matter.
5-6Gas Pressure and its MeasurementPressure = forceareaAtmospheric pressure arises from the force exerted by atmospheric gases on the earth’s surface.Atmospheric pressure decreases with altitude.
5-7Figure 5.2Effect of atmospheric pressure on a familiar object.
5-8Figure 5.3A mercury barometer.
5-9Figure 5.4 AThe Hg levels are equal because both arms of the U tube are evacuated.Closed-end manometerA gas in the flask pushes the Hg level down in the left arm.The difference in levels, h, equals the gas pressure, Pgas.
5-10Figure 5.4 BOpen-end manometerWhen Pgasis less than Patm, subtract hfrom Patm.Pgas< PatmPgas= Patm- hWhen Pgasis greater than Patm, add hto Patm.Pgas> PatmPgas= Patm+ h
5-11Table 5.1Common Units of Pressure
Sample Problem 5.1Converting Units of PressurePROBLEM:A geochemist heats a limestone (CaCO3) sample and collects the CO2released in an evacuated flask attached to a closed-end manometer. After the system comes to room temperature, Δh= 291.4 mm Hg. Calculate the COpressure in torrs, atmospheres, and kilopascals.PLAN:Construct conversion factors to find the other units of pressure.2
5-13The Gas LawsThe gas laws describe the physical behavior of gases in terms of 4 variables:pressure (P)temperature (T)volume (V)amount (number of moles, n)An ideal gasis a gas that exhibits linear relationships among these variables.No ideal gas actually exists, but most simple gases behave nearly ideally at ordinary temperatures and pressures.
5-14Figure 5.5Boyle’s law, the relationship between the volume and pressure of a gas.
5-15
V 1Por PV= constantAt fixed Tand n, Pdecreases as VincreasesPincreases as Vdecreases
5-16Figure 5.6 ABCharles’s law, the relationship between the volume and temperature of a gas.

  • Left Quote Icon

    Student Picture

  • Left Quote Icon

    Student Picture

  • Left Quote Icon

    Student Picture