Chemistry 222 DO NOT OPEN THE EXAM UNTIL YOU ARE READY TO TAKE IT! You may allocate a maximum of 80 continuous minutes for this exam.

Size: px

Start display at page:

Download "Chemistry 222 DO NOT OPEN THE EXAM UNTIL YOU ARE READY TO TAKE IT! You may allocate a maximum of 80 continuous minutes for this exam."

Chrystal Banks
5 years ago
Views:

1 Chmtry Sprg 09 Eam : Chaptr -5 Nam 80 Pot Complt fv (5) of th followg problm. CLEARLY mark th problm you o ot wat gra. You mut how your work to rcv crt for problm rqurg math. Rport your awr wth th approprat umbr of gfcat fgur. Rul for th tak-hom am. DO NOT OPEN THE EXAM UNTIL YOU ARE READY TO TAKE IT! You may allocat a mamum of 80 cotuou mut for th am. Trat th tm a though you wr takg th am th claroom. You may ot u your book, ot, lctroc ourc or ayo l to hlp. Rcor th tart a tm blow. Complt fv (5) of th v problm. CLEARLY mark th problm you o ot wat gra. You mut how your work to rcv crt for problm rqurg math. Rport your awr wth th approprat umbr of gfcat fgur. For cuo problm, b coc your awr. I ttoally lft ubtatal pac for ach problm, you o ot to u all of th pac prov. Oc you hav complt th am, g blow to affrm that t wa tak followg th rul abov. Th gatur your plg that th am wa complt a thcal mar! Th am u by th tart of cla, Moay, Fbruary 8. You may tur th am arlr f you wh. Start tm: E tm: Sgatur Dat

2 Complt fv (5) of th followg problm. CLEARLY mark th problm you o ot wat gra. You mut how your work to rcv crt for problm rqurg math. Rport your awr wth th approprat umbr of gfcat fgur. Do fv of problm -7. Clarly mark th problm you o ot wat gra. (6 pt ach). A oluto wa prpar by olvg.975 gram of a ol ampl cotag a ukow amout of mrcury a total of ml of oluto, whch wa labl oluto A. Bfor aaly, 5.00 ml of oluto A wa pptt to a ml volumtrc flak, m a lut to th mark to form oluto B. Th 0.00 ml of oluto B wa pptt to a 5.00 ml volumtrc flak, m a lut to th mark to mak oluto C. Aaly of oluto C trm that t ha a mrcury coctrato of.6 ppm. What wa th prct mrcury by ma th orgal ol ampl? You may aum a ty of.00 g/ml for all oluto.

3 . A Staar Rfrc Matral crtf to cota 45.4 ppm of a orgac cotamat ol. You aalyz th matral to charactrz a w mtho you ar vlopg. Your aaly gv valu of 47.8, 47.4, 45.6, 48., a 47. ppm. Evaluat th rult for upct ata a trm whthr your rult cat th prc of ytmatc rror your mtho at th 95% cofc lvl. Jutfy your awr. 3

4 3. Ac oluto ca b taarz ug prmary taar oum carboat, much lk ba oluto ca b taarz ug pur KHP a w lab. Blow ata from a ttrato of a oum carboat ampl wth a oluto of hyrochlorc ac of ukow coctrato. I th ttrato, appromatly 5 ml of tll watr wa u to olv th oum carboat that wa p from th wghg bottl to a Erlmyr flak. What th molarty of th hyrochlorc ac oluto wth t abolut ucrtaty? Ital ma of wghg bottl a oum carboat Fal ma of wghg bottl aftr ampl wa rmov Ital burt rag Fal burt rag Molar ma of oum carboat 3.384±0.000 g ±0.000 g.38±0.0 ml 39.54±0.0 ml ±0.000 g/mol 4

5 4. Complt both part a fw tc. (8 pt ach part) a. Why o ytmatc (trmat) rror typcally hav a largr mpact o th accuracy of a maurmt tha raom (trmat) rror? b. How th prct rcovry of a pk (fortf) ampl trm a how t uful valuatg th accuracy of a mtho? 5

6 5. You ar workg to vlop a w mtho for th trmato of th ulfur cott coal. If uccful, your mtho ha th pottal to b vry valuabl. To valat your mtho, you c to compar t to a tablh, Iutry Staar mtho. Th wght prct ulfur of four ffrt coal ampl (ach cotag ffrt amout of S) wa maur by th two ffrt mtho. Do your mtho gv rult that ar cott wth th Iutry Staar at th 95% cofc lvl? Sampl 3 4 Iutry Staar Mtho Your Mtho

7 6. A a rctly hr aalytcal chmt, you hav b tak wth trmg th tcto lmt for a aalytcal maurmt. You collct ata for fv blak a four taar oluto. Th ata a th rult of your calbrato curv ar blow. Dtrm th tcto lmt for th maurmt. You may gor ucrtat th lop a trcpt. Calbrato rlatohp: Sgal 44.9µA/ppm[coctrato] 9.3 µa Coctrato (ppm) Sgal (mcroamp) 0 (blak) 5.6, 0., 3.8,.3, Sgal (Amp) y R² Coctrato (ppm) 7

8 7. You hav b gv th tak of tachg a quattatv aaly tut, Al Thumb, th propr u of a Cla A burt for ttrato orr to obta hgh qualty quattatv rult. Clarly crb your tructo to th tut, clu rmr of commo ptfall Al houl avo. 8

9 9 Pobly Uful Iformato m' m a w a Dty of ar 0.0 g/ml Dty of balac wght 8.0 g/ml t ± µ ) ( y σ µ π σ B A C B A C B A C kow valu t calculat ( ) pool calculat t ( ) ( ) pool t calculat ( ) ( ) y m y) (y k m ( ) y D y m D y b y LOD y blak 3 ( ) ( ) calculat F rag gap Q calculat valu upct G calculat

Dgr of From Valu of Stut t Cofc Lvl (%) 90 95 99.5 99.9 6.34.706 7.3 636.6.90 4.303 4.089 3.598 3.353 3.8 7.453.94 4.3.776 5.598 8.60 5.05.57 4.773 6.869 6.943.

76 5 0.64 6 0.56 Grubb Tt for Outlr # of Obrvato G crtcal At 95% cofc 4.463 5.67 6.

10 Dgr of From Valu of Stut t Cofc Lvl (%) Valu of Q for rjcto of ata # of Obrvato Q (90% Cofc) Grubb Tt for Outlr # of Obrvato G crtcal At 95% cofc Crtcal Valu of F at th 95% Cofc Lvl Dgr of from for Dgr of from for

We need to first account for each of the dilutions to determine the concentration of mercury in the original solution:

We need to first account for each of the dilutions to determine the concentration of mercury in the original solution: Complt fv (5) of th followg problm. CLEARLY mark th problm you o ot wat gra. You mut how your work to rcv crt for problm rqurg math. Rport your awr wth th approprat umbr of gfcat fgur. Do fv of problm