F A. Review1 7/1/2014. How to prepare for exams. Chapter 10 - GASES PRESSURE IS THE FORCE ACTING ON AN OBJECT PER UNIT AREA MEASUREMENT OF PRESSURE

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est yourself wth old exam from my web page: SEE SYLLABUS Revew1 Chapters 10, 11, 13 Chapter 10 - GASES ressure What ca we measure?

1 How to prepare for exams 1. Uderstad EXAMLES chapter(s). Work RACICE EXERCISES 3. Work oe problem from each class of problems at ed of chapter 4. Aswer as may questos as tme permts from text web: 5. est yourself wth old exam from my web page: SEE SYLLABUS Revew1 Chapters 10, 11, 13 Chapter 10 - GASES ressure What ca we measure? he Gas Laws he Ideal Gas Equato artal ressures, Molecular Weght & Desty Ketc Molecular heory Real Gases RESSURE IS HE FORCE ACING ON AN OBJEC ER UNI AREA F A MERCURY BAROMEER MEASUREMEN OF RESSURE he relatoshp betwee pressure () ad the heght (h) of a lqud a barometer s = g d h where g => costat accelerato of gravty ad d => desty of lqud maometer 1

Fg 10.3 WHA CAN WE MEASURE? RESSURE EMERAURE VOLUME AMOUN Fgure 10.3 A mercury maometer. hs devce s sometmes employed the laboratory to measure gas pressures ear atmospherc pressure.

2 Fg 10.3 WHA CAN WE MEASURE? RESSURE EMERAURE VOLUME AMOUN Fgure 10.3 A mercury maometer. hs devce s sometmes employed the laboratory to measure gas pressures ear atmospherc pressure. BACK Stadard (S) Codtos Stadard emperature = 0C = K Stadard ressure = 1 atm OHER USEFUL VALUES at S stadard volume =.4 Lters Whe = 1 mole Revew of Gas Laws Boyle s Law. V a costat Charles s Law V a costat Avogadro s Law.. V a costat Combed Laws V a cos ta t For a deal gas HE IDEAL GAS EQUAION V = R 1. the molecules have NO volume. molecules do NO attract (or repel) each other.

3 ALICAIONS OF HE IDEAL GAS EQUAION 1. Gas Desty weght / volume. Molecular Weght grams / mole 3. artal ressures 4. Gas Volumes Chemcal Reactos GAS DENSIY V grams MW R V MW = grams R Desty grams volume R MW What happes to the desty as (a) the gas s heated a costat-volume cotaer; (b) the gas s compressed at costat temperature; (c) addtoal gas s added to a costat-volume cotaer? Aswer: (a) o chage, (b) crease, (c) crease MOLAR MASS (MOLECULAR WEIGH) From V = R grams moles MW gr MW V Gas Mxtures ad artal ressures total where s the mole fracto otal A L sample of dry ar at 5.0 o C has the followg composto: N O g g Ar g ad CO g. 3

4 What s the partal pressure of each gas ad what s the otal pressure? 1 st Covert grams to moles d Use Ideal Gas Equato L at 5.0 o C wth g N (a) What s the partal pressure of N??? 1 mol ( g) x mol 8 g N R N V ( )(0.0806)(5 73) L at 5.0 o C wth O (a) partal pressure of O???? 1 mol ( g ) x mol 3 g O R O V ( )(0.0806)(5 73) he total pressure s the sum of the partal pressures Repeat for Argo: = Repeat for CO : = total = troge + osyge + argo + carbodoxde total = total = atm he va der Waals Equato Real Gases Devatos from Ideal Behavor Corrects for molecular volume R V b a V Corrects for molecular attracto 4

5 Real Gas Ideal Gas LOW ressures (ot much gas) LARGE volume (lots of room betwee molecules) HIGH emperature (molecules are movg too fast to teract) Chapter 11 INRA molecular forces INER molecular forces Chemcal BONDS Formed BEWEEN ELEMENS are INRA molecular forces Chemcal BONDS Formed BEWEEN MOLECULES (&/or IONS) are INER molecular forces INER Molecular Forces Much weaker tha tra molecular forces. Several types of forces: 1. Io dpole. Dpole dpole 3. Lodo Forces => Istataeous duced dpole (dsperso forces) 4. Hydroge bods. Secto 11. ONLY HIS MAERIAL NO COVERED IN EXAM ropertes of Lquds hase Chages Vapor ressure hase Dagrams Chapter 13 Solutos ad her ropertes Solublty Rules Chapter 4 Factors that affect Solublty ressure (Hery s Law) emperature Cocetrato Molecular weght Collgatve ropertes Molecular solutos Ioc solutos 5

EMERAURE EFFECS As temperature creases, solublty of solds geerally creases BU Not Always Sometmes, solublty decreases as temperature creases RESSURE EFFECS Hery s Law: he solublty s drectly

6 EMERAURE EFFECS As temperature creases, solublty of solds geerally creases BU Not Always Sometmes, solublty decreases as temperature creases RESSURE EFFECS Hery s Law: he solublty s drectly proportoal to the pressure of the gas over the soluto. S g = k g CONCENRAION EFFECS he amout of solute preset a gve amout of soluto IONIC Or MOLECULAR? SRONG ELECROLYES A substace that completely ozes ypes of Electrolytes 1. SRONG ELECROLYES A substace that completely ozes Strog Acds [7] Strog Bases [7] Soluble Salts. WEAK ELECROLYES A substace that does NO completely oze Weak Acds / Bases Slghtly Soluble Salts arts per Mllo {ppm} arts per mllo (ppm) ca be expressed as 1 mg of solute per klogram of soluto If the desty of the soluto s 1g/mL, the 1 ppm = 1 mg solute per lter of soluto 6

7 Moles of A X A otal umber of moles Moles of solute Molarty Lters of SOLUION Moles of solute Molalty = Klograms of SOLVEN Collgatve ropertes Collgatve ropertes: hese propertes deped ONLY o the Number of solute partcles soluto ad NO ON the ature of the solute partcles. WHY SUDY CONCENRAION? 7

We have already referred to a certain reaction, which takes place at high temperature after rich combustion.

ME 41 Day 13 Topcs Chemcal Equlbrum - Theory Chemcal Equlbrum Example #1 Equlbrum Costats Chemcal Equlbrum Example #2 Chemcal Equlbrum of Hot Bured Gas 1. Chemcal Equlbrum We have already referred to a