8 Solved Problems on Steady State Approximation - Final Exam | CH 440, Exams of Physical Chemistry

Download 8 Solved Problems on Steady State Approximation - Final Exam | CH 440 and more Exams Physical Chemistry in PDF only on Docsity! Key to CH 442, Final exam June 13, 2006 1. (10 points) Throughout the term, we have made several approximations to simplify the subject of study. Describe the following approximations using two phrases, including the basis and the ignored factors in the approximation. (a) Dilute gas approximation (b) High rotational temperature approximation (c) Steady state approximation (d) Pre-equilibrium approximation (e) Gaussian chain approximation (@) Tare * Tntrrmeleato, Ltoractn, Cr a bedwern odfacomt molewder ey Deane i caatara tm vet, nr r peas: Wigt U kT >> Yer Ev-py ce) Oy cre chowfar of Ounce Aredion ad nate cdots, (sare after wi dach of yen pahermed ote hos bw Cun Ton, yo yosee Lene vote dadermininp stop tala being Prtranadtete Crrtsfyetren owt 2 TH pce SUowtr bones » 19%e dare Me = a lon (at stop : A ote sc Nv . (15 points) An experimental physical chemist needs to design several experiments to achieve several goals. Suggest the plots that he/she needs to make. (a) To confirm the order of a reaction to be 2™ order. (b) To determine the Michaelis constant Kyy and the turn over number ea, based on = eal F ly 14+ Ky 1S] (c) To determine the activation energy in a bimolecular reaction using the Arrhenius equation. ta 2 oe eg @) SF eet ta ta. Pet EA vs. %. |) Reno. fe) lez ne eet Ec [kee WA ~ “pet pete ae 5. (10 points) (a) Human blood plasma contains approximately 40 g albumin (M = 69 kg/mol) and 20 g of globulin (M = 160 kg/mol) per liter of solution. Calculate the colloid osmotic pressure at 37° C in the dilute solution limit. (b) The diffusion coefficient of myoglobin is 1.24 x 10"'° m’/s at 20°C and the viscosity of water is 0.001 Pa-s. The density of pure myoglobin is 1.33 g/cm?. What is the molar mass assuming that the protein is spherical and not hydrated by water? @) T= RTEM ) bo > 4 28a G11) «Geta veer ) = Paradox ora = 1.8 Pa cb) Dee2ns<e se wa /s Ta20%c n= v.00 Pa'S P= 1-23 5/¢ 3 = ket D> Gaye = ED fw = Aan’? P Ma Seasick © 339/ [ee HG WX se Sd (4007 wale = UT By /moak Gxduexo.ea| KI2G RS 3 Je 6. (10 points) A solution of methyl radicals has a viscosity of 10° kg/(m-s) al 300 K. the diffusion coefficient of ‘CH; is 10° m’/s, (a) Determine the numerical value of the hydrodynamic radius of -CH3. (b) What is the maximum value of the diffusion controlled rate coefficient (in units of (m?/(mol's)) for methyl radical recombination? fein ~ 7oiek a= co nfs ay ge ee _ ksT G) 9 gage ea Seige Be is wo (pee aiae ee A ae fxd (o> xe bh ken an RdD-4% See? eee =beed (mA nests) fo Neos G02 xiord x oO 7. (15 points) (a) Calculate the frequency of a single quantum proton resonance in a 10 T magnetic field. (b) Write the expression for the nuclear spin partition function for a proton in a magnetic field, and cvaluate the partition function (to two significant figures) for a proton in a 600 MHz NMR spectrometer at 300 K. (c) Plot the NMR spectrum of an A:X spin system and explicitly label the A and X resonances. 2 @) G20, ge = 9 OT Sun 6 ath, = oe ee A = 6 S707) KIS = Bun mth “Zoe. (bh) ee jv ae G&G My ee =a ee eke ay 4 Senter et Mle ket < Rise Lov coe x 6x8 /2Bxio 2 fe Le &é a= oe x 107 Ba gee ET e. =1.2