Fculty of turl nd Agriculturl Science Chemitry Deprtment Emintion Anlyticl Chemitry II CMY 83 Dte: 9 ov 0 Lecturer: Prof I Cukrowki Time: 0 min Dr P Forbe Mrk: 00 Pge: Intruction: Anwer ll the quetion. All nwer (clcultion, ketche, nd digrm) mut be given in blck or blue ink. All clcultion mut be hown in full. Dtheet re provided on pge 6-.
SECTIO Dr P Forbe 7 MARKS QUESTIO Redo titrtion 7 MARKS.) In redo titrtion, the initil potentil i: ) Equl to the tndrd electrode potentil of the reduction hlf-rection b) Equl to the tndrd electrode potentil of the oidtion hlf-rection c) Equl to the tndrd electrode potentil of the hydrogen electrode hlf-rection d) Depend on the type of electrode employed e) one of the bove () You need only write the correct letter in your nwer..) The concentrtion of ferrou ion in olution w determined by titrtion with Ce 4+ in M HCl. ) Wht i the relevnt chemicl rection eqution? () b) Wht would the ytem potentil be t equivlence? (4) c) How would the potentil t equivlence chnge if the nlyte nd titrnt concentrtion were both hlved? () QUESTIO Completion titrtion 7 MARKS.) EDTA i commonly ued titrnt in compleometric titrtion. Drw digrm to illutrte how the form of EDTA vrie with ph nd eplin how thi fct cn be ued to provide electivity in metl ion determintion. (5).) Briefly define the following term with repect to compleometric titrtion: ) Lignd () b) Dentte () QUESTIO 3 Precipittion titrtion 6 MARKS A 50.00 ml wter mple w teted for it chloride content downtrem of delintion wter tretment plnt. 0.00 ml of 0.00 M AgO 3 w dded to the mple nd the ece AgO 3 w bck-titrted with 6.5 ml of 0.0550 M KSC. Determine the chloride content of the wter mple in mgl - nd clculte the % chloride removl by the proce if the incoming wter contined 800 mgl - chloride. (6) QUESTIO 4 eutrliztion titrtion 7 MARKS Clculte the ph in neutrliztion titrtion where 50.00 ml of 0.000 M nitrou cid i titrted with 0.00 M OH when: ) 0.00 ml of OH h been dded. (4) b) 5.00 ml of OH h been dded. (3)
SECTIO Prof I CUKROWSKI (33 MARKS) STATISTICAL DATA TREATMET QUESTIO 9 MARKS A.309 ± 0.00 g of olid mple contining -Hydroybenzoic cid, (OH)C 6 H 5 COOH (MW 38. g/mol) w nlyed uing cid-be titrtion method. The end point of titrtion (EP) w reched t 43.85 ± 0.05 ml with n initil reding 0.5 ± 0.05 ml when 0.056 ± 0.0008 M OH titrnt olution w ued. Clculte weight % of -Hydroybenzoic cid in the olid mple nd report the vlue with ttiticlly vlid uncertinty. QUESTIO MARKS The tock olution of nitric cid w tndrdied nd the molr concentrtion obtined from replicte titrtion (uing tndrd OH olution) were: 0.44, 0.454, 0.460, 0.463, 0.475, 0.48 nd 0.483 M. ) Doe the dt et contin n outlier t the 95 % confidence level? 3 mrk b) Report the concentrtion, with td. devition, of the nitric cid olution. mrk c) Wht i the confidence level within which the true vlue of the concentrtion of the nitric cid olution i epected t the 99% probbility level? 3 mrk d) Report the ph, with ttiticlly vlid uncertinty, of the nitric cid olution. 3 mrk Py ttention to the number of ignificnt figure. QUESTIO 3 7 MARKS Si different blood mple were nlyed for the level of choleterol uing new method A nd well-etblihed method B. Reult obtined re: Choleterol (mg / L) in mple o. Method 3 4 5 6 A.46..84.97.3.35 B.3.08.67.85.8.5 Do the dt indicte bi in the new method A (t the 95 % Confidence Level) indicting ytemtic error in tht procedure? 3
QUESTIO 4 6 MARKS The olubility product K p for the M S() lt i known to be 6.0(± 0.4) 0. Wht i the olubility nd uncertinty in the clculted olubility of thi lt? SECTIO 3 Prof I Cukrowki (40 MARKS) CHEMICAL EQUILIBRIA QUESTIO 5 8 MARKS ) How mny grm of BCl.H O (MW 44.7 g/mol) you need to prepre 50 ml of 0.5 M chloride ion olution? mrk b) It w etblihed tht thi regent w contminted by CCl (MW 8.8 g). The content of clcium in the olid mple w found to be 4750 ppm (w/w). Wht w the percentge decree in the molr Brium ion concentrtion cued by thi contmintion? 6 mrk QUESTIO 6 6 MARKS A 0.03 M olution of wek cid HAc h ph. t 5 C. Wht i the diocition contnt of thi cid? QUESTIO 7 6 MARKS You re to prepre 0.50 L of buffer olution which i 0.0 M in cid nd h ph 4.9 nd. The following component re vilble: ).00 M Acetic cid olution, K.75 0 5 b) olid odium cette (M 8.0337 g) How mny ml of HAc olution nd how mny grm of the lt re required to prepre the olution? Decribe in ome detil how you would proceed with the olution preprtion. 4
QUESTIO 8 0 MARKS Clculte the chnge in ph of 50 ml olution being 0.8 M in HAc nd 0.6 M in Ac fter the ddition of 5.0 ml of.0 M OH. K 3. 0 5. QUESTIO 9 0 MARKS You hve olution of 50.0 ml of 0.0 M AgO 3. To thi olution 50.0 ml of 0.5 M lignd olution w dded. Thi lignd form trong comple with ilver ion, AgL, nd it overll formtion contnt log β 0.5. Wht chnge in potentil of ilver indictor electrode would be recorded t 5 C? Aume tht AgL i the only ignificnt pecie of ilver preent. E (Ag) 0.799 V. At 5 C: (RT/nF)ln (0.0596/n)log in V 5
STADARD ELECTRODE POTETIALS E 0 (Sn 4+ /Sn + ) +0.54 V E 0 (Fe(C) 3-6 /Fe(C) 4-6 ) +0.360 V E 0 (Fe 3+ /Fe + ) +0.77 V E 0 (Tl 3+ /Tl + ) +.50 V E 0 (Tl + /Tl) -0.336 V TABLE OF DISSOCIATIO COSTATS Acid K (5 C) Acid K (5 C) Be K b (5 C) H 3 PO 4 7. 0 3 H S 9.5 0 8 H COH.3 0 4 HO 7. 0 4 HC 3 H 5 O 3.4 0 4 C 5 H 5.7 0 9 H CO 3 4.5 0 7 HS.0 0 9 H OH. 0 8 CH 3 COOH.8 0-5 3+ Co(H O) 6.0 0 5 H 3.8 0 5 HClO 3.0 0 8 3+ Fe(H O) 6.0 0 3 CH 3 H 4.4 0 4 C 6 H 5 COOH 6.3 0 5 3+ Al(H O) 6.4 0 5 CO 3.8 0 4 HC 6. 0 0 (CH 3 ) H 5.8 0 4 HF 7. 0 4 C 6 H 5 H 6.4 0 4 TABLE OF SOLUBILITY PRODUCT COSTATS Compound K p (5 C) Compound K p (5 C) AgBr 5.0 0 3 AgIO 3 3. 0 8 Ag CO 3 8. 0 AgI 8.3 0 7 AgCl.8 0 0 Ag S 8 0 5 AgC. 0-6 AgSC. 0 STADARD AD FORMAL ELECTRODE POTETIALS E 0 (V) H + + e - H (g) 0.000 Ce 4+ + e - Ce 3+ +.44 Fe + + e - Fe () -0.440 Fe 3+ + e - Fe + +0.77 (0.700 in M HCl) Sn + + e - Sn () -0.36 (-0.6 in M HClO 4 ) Sn 4+ + e - Sn + +0.54 (0.4 in M HCl) UO + + 4H + + e - U 4+ + H O +0.334 V 3+ + e - V + -0.55 VO + + H + + e - V 3+ + H O +0.359 V(OH 4 ) + + H + + e - VO + + 3H O +.00 (.0 in M HCl, HClO 4 ) α E E o c 0.059 [ C] [ D] log n [ A] [ B] K K K K [ ] + K K K K 3 4 4 + 4 + 3 + H ] + K[ H ] + KK[ H ] + KKK3[ H + WHERE K.0 X 0 - ; K.4 X 0-3 ; K 3 6.9 X 0-7 ; K 4 5.50 X 0 - OTE: α 4.5 X 0-5 FOR [H + ].00 X 0-6 M d b 3 4 6
7 y log y ntilog y b c b c ± + ± ± ( ) ( ) ( ) c b y + + c b y + + ± c b y c b y y ± y y y 434 0. y y 303.
Stndrd devition i ( i m ) Reltive tndrd devition (RSD) RSD m 000 ppt Coefficient of vrition (CV) CV m 00 % Stndrd error of the men m z ( µ ) σ m µ ± m zσ d m t ± ( d m ) pooled ( i m ) + ( j m ) i j + +... +... Q ep q w n m µ ± t m m ± t pooled + min m > t b + 8
Criticl vlue for the rejection Qutient, Q o of obervtion Q crit t Confidence: 80% 90% 95% 96% 98% 99% 3 0.886 0.94 0.970 0.976 0.988 0.994 4 0.679 0.765 0.89 0.846 0.889 0.96 5 0.557 0.64 0.70 0.79 0.780 0.8 6 0.48 0.560 0.65 0.644 0.698 0.740 7 0.434 0.507 0.568 0.586 0.637 0.680 8 0.399 0.468 0.56 0.543 0.590 0.634 9 0.370 0.437 0.493 0.50 0.555 0.598 0 0.349 0.4 0.466 0.483 0.57 0.568 0.33 0.39 0.444 0.460 0.50 0.54 0.38 0.376 0.46 0.44 0.48 0.5 3 0.305 0.36 0.40 0.45 0.465 0.503 4 0.94 0.349 0.396 0.4 0.450 0.488 5 0.85 0.338 0.384 0.399 0.438 0.475 6 0.77 0.39 0.374 0.388 0.46 0.463 7 0.69 0.30 0.365 0.379 0.46 0.45 8 0.63 0.33 0.356 0.370 0.407 0.44 9 0.58 0.306 0.349 0.363 0.398 0.433 0 0.5 0.300 0.34 0.356 0.39 0.45 9
0
THE PERIODIC TABLE OF THE ELEMETS H.0 He 4.00 3 Li 6.94 4 Be 9.0 5 B 0.8 6 C.0 7 4.0 8 O 6.00 9 F 9.00 0 e 0.8.99 Mg 4.3 3 Al 6.98 4 Si 8.09 5 P 30.97 6 S 3.07 7 Cl 35.45 8 Ar 39.95 9 K 39.0 0 C 40.0 Sc 44.96 Ti 47.87 3 V 50.95 4 Cr 5.00 5 Mn 54.94 6 Fe 55.85 7 Co 58.93 8 i 58.69 9 Cu 63.55 30 Zn 65.39 3 G 69.7 3 Ge 7.6 33 A 74.9 34 Se 78.96 35 Br 79.90 36 Kr 83.80 37 Rb 85.47 38 Sr 87.6 39 Y 88.9 40 Zr 9. 4 b 9.9 4 Mo 95.94 43 Tc 98.9 44 Ru 0.07 45 Rh 0.9 46 Pd 06.4 47 Ag 07.87 48 Cd.4 49 In 4.8 50 Sn 8.7 5 Sb.76 5 Te 7.60 53 I 6.90 54 Xe 3.9 55 C 3.9 56 B 37.33 57 L 38.9 7 Hf 78.49 73 T 80.95 74 W 83.84 75 Re 86. 76 O 90.3 77 Ir 9. 78 Pt 95.08 79 Au 96.97 80 Hg 00.59 8 Tl 04.38 8 Pb 07.0 83 Bi 08.98 84 Po 08.98 85 At 09.99 86 Rn.0 87 Fr 3.0 88 R 6.03 89 Ac 7.03 04 Rf 6. 05 Db 6. 06 Sg 63. 07 Bh 6. 08 H 65 09 Mt 66 58 Ce 40. 59 Pr 40.9 60 d 44.4 6 Pm 44.9 6 Sm 50.36 63 Eu 5.97 64 Gd 57.5 65 Tb 58.93 66 Dy 6.50 67 Ho 64.93 68 Er 67.6 69 Tm 68.93 70 Yb 73.94 7 Lu 74.97 90 Th 3.04 9 P 3.04 9 U 38.03 93 p 37.05 94 Pu 44.06 95 Am 43.06 96 Cm 47.07 97 Bk 47.07 98 Cf 5.08 99 E 5.08 00 Fm 57.0 0 Md 58.0 0 o 59.0 03 Lr 6.