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EXAM 1 – Dr. Vedernikov Full Name: _________________________________ First letter of your Last Name : Please PRINT “ I pledge on my honor that I have not given or received any unauthorized assistance on this examination” Signature Date This exam contains 6 pages in total including this title page:  9 questions on pages 2 - 4 (do NOT separate these pages and the title page)  some physical constants on page 4,  formulas on p. 5, and  the Periodic Table of the Elements on page 6 (you may detach it). Check if you have all of that before you begin. You may use any blank pages as a scratch paper. Put your answers ONLY in the space provided. Examination rules:  You may not begin until everyone has an exam  When time is called, put your pencil down and remain in your desk  After all exams have been collected, you will be dismissed Question 1: _____/10 pts Question 6: ____/12 pts Question 2: _____/14 pts Question 7: ____/10pts Question 3: _____/10 pts Question 8: ____/10pts Question 4: _____/12 pts Question 9: ____/12 pts Question 5: ____/10 pts TOTAL POINTS : _________/100

2 1. (10 pts) A mixture of air and a vaporized fuel in a car engine cylinder was compressed to a volume of 0.30 L. Upon ignition 1.50×10 4 J of heat was produced and the gaseous products expanded against forces of a constant external pressure of P = 10.5 atm. The final volume of the gaseous products was 3.60 L. Find the change of the internal energy,  E , of the gaseous products in Joules . Show your work:  E = ____ _________ J Sign magnitude 2. (14 pts) a) (4 pts) Write balanced equation for the formation reaction for NH 4 NO 3 ( s ), indicate states of all chemicals: b) (10 pts) Use the thermochemical equation below and calculate the standard enthalpy change in kJ for the reaction that fully consumes 1.000 kg of NH 4 NO 3 ( s ) (formula mass 80.04 amu ). 2NH 4 NO 3 ( s )  2N 2 ( g ) + O 2 ( g ) + 4H 2 O( l )  H o rxn = -412.0 kJ Show your work: Enthalpy change = ____ _________ k J Sign magnitude 3. (10 pts) A liquid diethyl ether (molar mass 74.1 g/mol) was injected into a flask filled with Ar( g ) (molar mass 39.9 g/mol) at 20 o C and initial pressure 760.0 mmHg. As the liquid ether evaporated, the pressure inside the flask grew from 760.0 mmHg to 1198.0 mmHg. a) What is the molar fraction of ether vapors in the gas phase? b) Is the density of the gaseous mixture lower, greater or the same, as compared to pure Ar( g )? Show your work: Molar fraction of ether( g ): ________ Density of the gaseous mixture vs . that of Ar (circle one): same greater lower

3 4. (12 pts) Use the < and/or = signs and rank the following. Assume otherwise identical conditions. a) Ne( l ), HF( l ), NH 3 ( l ), according to increasing boiling point: (lowest) __________________ (highest) b) O 2 ( g ), Ar( g ), CH 4 ( g ), according to increasing root mean square speed: (lowest) ______________ (highest) c) NaF, RbI, KBr, according to their ionic lattice energy: (most negative)_________________(least negative) 5. (10 pts) The molar concentration of CO 2 ( aq ) in a carbonated drink placed in a sealed can is 0.122 M. Find the partial pressure of CO 2 ( g ) in atm above the liquid in the can at 25.0 o C. The Henry’s law constant for CO 2 solutions in water, k H , is 0.0340 mol L -1 atm -1 at 25.0 o C. Show your work. Answer : ________ atm 6. (12 pts) Use the < and/or = signs and rank the following aqueous solutions. Assume otherwise identical conditions. a) HClO 4 , H 2 SO 4 , glucose, all 1 molal , by their freezing point: (most negative) ___________________________________ (least negative) b) HCl, KNO 3 , K 2 CO 3 , all 1 molal , by increasing water vapor pressure, P H2O , at 25 o C: (lowest P H2O ) ___________________________________________________ (highest P H2O ) c) 0.5 m HCl, 0.1 m HCl, 1.2 m HCl, by increasing molar fraction of HCl( g ) in the vapor phase,  G HCl : (lowest  G HCl ) ________________________________ (highest  G HCl ) 7. (10 pts) The initial rate of consumption of O 2 ( g ) in the following reaction is 0.050 M/s: 4NH 3 ( g ) + 5O 2 ( g )  4NO( g ) + 6H 2 O( g ) What is the initial rate of formation of NO( g ) in M/s? Show your work: Rate of formation of NO( g ) = ______________ M/s

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4 8. (10 pts) The reaction 2 X + Y  Z is first order in [ X ] and 1/2 order in [ Y ]. The initial rate of this reaction was measured in some mixture of X and Z . How much will the initial rate of this reaction change if the solution is diluted three-fold? Show your work: The initial rate will (increase) (not change) (decrease) by a factor of ____________ circle the correct answer above 9. (12 pts) The rate law for a reaction below is rate = k [ t -BuCl]: t -BuCl( aq ) + H 2 O( l )  t -BuOH(aq) + HCl( aq ) At 20 o C the reaction is 75.0% complete (75.0% of t -BuCl is consumed) after 208 hours. What is the reaction rate constant? After what time in hours will the reaction be 99.0% complete? Show your work: Reaction rate constant = __________ _____ magnitude units Reaction time at 99.0% conversion : ________ h Some Physical Constants and conversion factors Gas constant, R = 0.08206 L×atm/(mol×K) = 8.314 J /(mol×K) 1 atm = 760.0 mmHg = 101325 Pa ; 1 m 3 = 1000 L

5 Important formulas 1 st law of thermodynamics:  E = q + w Pressure-volume work: w = - P  V Heat transferred to a system: q sys = C s × m sys ×  T sys Enthalpy:  H =  E + P  V when P = const Reaction Enthalpy from bond energies:  H rxn =  (energies of all bonds broken) –  (energies of all bonds formed) Standard Reaction Enthalpy from standard enthalpies of formation: ∆࠵? ࠵? ൌ ෍ ࠵? ࠵? ∆࠵? ࠵? ࠵? ሺ࠵?࠵?࠵?࠵?࠵?࠵?࠵?࠵?ሻ െ ෍ ࠵? ࠵? ∆࠵? ࠵? ࠵? ሺ࠵?࠵?࠵?࠵?࠵?࠵?࠵?࠵?࠵?ሻ The ideal gas law: PV = nRT Ideal gas density: Density= (Molar mass)P RT Dalton’s law of partial pressures: P total = P A + P B + P C + … Molar fraction of a component A in a mixture of gases:  A = n A / n total = P A /P total Van der Waals’ equation: ൬࠵? ௥௘௔௟ ൅ ࠵? ቀ ௡ ௏ ೝ೐ೌ೗ ቁ ଶ ൰ ሺ࠵? ௥௘௔௟ െ ࠵?࠵?ሻ ൌ ࠵?࠵?࠵? Gas average kinetic energy: ࠵?࠵? തതതത ൌ ଷ ଶ ࠵?࠵? Root-mean-square speed of a gas particles: ࠵? ࠵?࠵?࠵? = ට ଷோ࠵? ࠵? Clausius-Clapeyron equation: ࠵?࠵? ሺ࠵? ࠵? / ࠵? ࠵? ሻ ൌ – ሺ࠵? / ࠵? ࠵? െ ࠵? / ࠵? ࠵? ሻ∆࠵? ࠵?࠵?࠵? / ࠵? Enthalpy of dissolution of ionic solids in water:  H sol =  H hydr, total -  H lat Ionic crystal lattice energy: ࠵?࠵?࠵?࠵?࠵?࠵?࠵? ࠵?࠵?࠵?࠵?࠵?࠵?࠵?࠵? ∝ ሺ࠵?࠵?࠵?࠵?࠵?࠵? ࠵?࠵?࠵?࠵?࠵?࠵?ሻൈሺ࠵?࠵?࠵?࠵?࠵? ࠵?࠵?࠵?࠵?࠵?࠵?ሻ ሺ࠵?࠵?࠵?࠵?࠵?࠵? ࠵?࠵?࠵?࠵?࠵?࠵?ା࠵?࠵?࠵?࠵?࠵? ࠵?࠵?࠵?࠵?࠵?࠵?ሻ Entropy of a system: S = ( R/N A ) × ln  Gibbs free energy:  G sys =  H sys - T  S sys The Henry’s law: S gas = k H P gas The Raoult’s Law: P solvent = P° solvent ×  solvent Boiling point elevation:  T b = BP solution – BP pure solvent = K b × i × m Freezing point depression:  T f = FP pure solvent – FP solution = K f × i × m Osmotic pressure:  = i × M × RT Rate of reaction aA + bB  cC + dD : Integrated rate laws for A  products. 0 order: [A] = [A] 0 - kt 1 st order: ln [A] = ln [A] 0 – kt ; reaction half-life t 1/2 = ln(2)/k 2 nd order: ࠵? / ሾ࠵?ሿ ൌ ࠵?࠵? ൅ ࠵? / ሾ࠵?ሿ ࠵? Arrhenius equation: k = A exp(- E a / RT )

6 Periodic Table of the Elements MAIN-GROUP ELEMENTS MAIN-GROUP ELEMENTS 1 18 1 1 H 1.008 2 13 14 15 16 17 2 He 4.003 2 3 Li 6.941 4 Be 9.012 5 B 10.81 6 C 12.01 7 N 14.01 8 O 16.00 9 F 19.00 10 Ne 20.18 d-BLOCK ELEMENTS 3 11 Na 22.99 12 Mg 24.31 3 4 5 6 7 8 9 10 11 12 13 Al 26.98 14 Si 28.09 15 P 30.98 16 S 32.07 17 Cl 35.45 18 Ar 39.95 4 19 K 39.10 20 Ca 40.08 21 Sc 44.96 22 Ti 47.87 23 V 50.94 24 Cr 52.00 25 Mn 54.94 26 Fe 55.85 27 Co 58.93 28 Ni 58.69 29 Cu 63.55 30 Zn 65.41 31 Ga 69.72 32 Ge 72.61 33 As 74.92 34 Se 78.96 35 Br 79.90 36 Kr 83.80 5 37 Rb 85.47 38 Sr 87.62 39 Y 88.91 40 Zr 91.22 41 Nb 92.91 42 Mo 95.94 43 Tc (97.9) 44 Ru 101.1 45 Rh 102.9 46 Pd 106.4 47 Ag 107.9 48 Cd 112.4 49 In 114.8 50 Sn 118.7 51 Sb 121.8 52 Te 127.6 53 I 126.9 54 Xe 131.3 6 55 Cs 132.9 56 Ba 137.3 57-71 72 Hf 178.5 73 Ta 180.9 74 W 183.8 75 Re 186.2 76 Os 190.2 77 Ir 192.2 78 Pt 195.1 79 Au 197.0 80 Hg 200.6 81 Tl 204.4 82 Pb 207.2 83 Bi 209.0 84 Po ( 209.0 ) 85 At ( 210.0 ) 86 Rn ( 222.0 ) 7 87 Fr ( 223.0 ) 88 Ra ( 226.0 ) 89-103 104 Rf (261.1) 105 Db (262.1) 106 Sg (263.1) 107 Bh (262.1) 108 Hs (265) 109 Mt (266) 110 Ds (271) 111 Rg (272) 112 Cn (285) 113 Nh (284) 114 Fl (289) 115 Mc (288) 116 Lv (292) 117 Ts (294) 118 Og (294) LANTHANIDES AND ACTINIDES 6 Lanthanides 57 La 138.9 58 Ce 140.1 59 Pr 140.9 60 Nd 144.2 61 Pm ( 144.9 ) 62 Sm 150.4 63 Eu 152.0 64 Gd 157.3 65 Tb 158.9 66 Dy 162.5 67 Ho 164.9 68 Er 167.3 69 Tm 168.9 70 Yb 173.0 71 Lu 174.0 7 Actinides 89 Ac ( 227.0 ) 90 Th 232.0 91 Pa 231.0 92 U 238.0 93 Np ( 237.1 ) 94 Pu ( 244.1 ) 95 Am ( 243.1 ) 96 Cm ( 247.1 ) 97 Bk ( 247.1 ) 98 Cf ( 251.1 ) 99 Es ( 252.1 ) 100 Fm ( 257.1 ) 101 Md ( 258.1 ) 102 No (259.1) 103 Lr (260.1)

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