Lab 6

Pre-Laboratory Assignment Name _%_EA\;{_C&(:[-_‘&)___ Lab Exercise 6: Liquid Density and Molarity Lab Section ¢\ Pre-Laboratory Questions Answer the following questions accurately using full sentences. 1. Why do you need to know and record the temperature of the water in Activity 1? TIX s ampotiony X0 Vanows and Tecord dne \-cx\f\?ao\-urc OF Mae W oXEL, VECOSDR Yae *em\;mwre \m\-xyo‘;-z Moe gecS ™. For @xonnp\s, e c%)oo«w\e:\ W;“:uu\o:; ~roxe ~ e Op. ber ; TS s \:ocmt?_ (e o\, Yee remgermtuce iedS o 2. Explain why the density unit of g/cm? is quivalent to g/mL. " e derSiy Omk of Afcen S GOUNONAY YO o/l pecouse Vel T\ cow 3. Explain the purpose of the calibration graph. T O CONOONON acogh (,a‘ooi*- S Ragv ol Yook e Yoo CoNDOXNON CocNe. e CoXdorodon CoNT Yo oy . : \'\C\{ e osed\ YO \oen \sdw\'(-o\\_\o(\ OQ o u(\\h( ch(\ 601081'0"‘03'- Lab 6: Measurements of Liquid Density and Molarity o

4. Look at the graph below and state in words the relationship between the applied force and the voltage experienced by the system. Visually interpolate to determine the approximate voltage when a force of 160 Ibs is applied. What is the approximate applied force if the system exhibits a voltage of 0.75 units? How could these values be determined exactly? Load Cell Calibration Curve 35 3 ’ y =0.0118*x + 0.1833 25 - . % 15 > ) N ! ' 4 0s 7./ X 2 0 50 100 150 200 ’ 250 300 Applied Force (Ib.) | Source: hltD1//WWW.rflakka—mcketll'y.net/strainlc.htn-n PSS xne oV TS Coce. \nCelRosSeES, 5o d:cg *:(\ei \g’\\*%c, BRSOl Ondes o ESSITVE CertrIoNon. QL@ ;W:\ \1.'3 . e Bes oG ote w ok \LON\GS, Ve 0_\,\:0%&«\ — 20 VNS, The QQQroxfch\—:t oghied oxte [ WS AS S o O e o ALOON TN\ T NaeSe. Nalues e, e €\ N o \@3z3 Cn Ve OUSeok- | 5. The volumetric pipet you sign out from your TA may be marked with “TD +0.04mL" or “TD 20°C +0.04mL". Explain this notation that might be found near the top of the pipet stem. Explain why the last drop is not blown out of the pipet. ) Ths r\g)\oéc'\of\ AtonShedes YOX Ve piper Nad veen L Colomded AO’C LOWN ¥R oRFewnce \evel of »o0.0 \_m\. Ve COMIOR Volume YO e aWN\ereh . The Colbrodion O(:;. Xee peX YOED \NYO O LA ON e, go(((:c:;f C:-U\%‘or\ :aroe.\? Cowrse €ome. ofF Ane \'\o.\u\& ’VS mmooo* C;i - woex . The \oex el 'S no N \*\\\ :TQ e)*:\ e\oe?c:»ee W coouId enpoex e NOVWOM e ex , M.‘nc> \¥ \o Yo .\‘\m(CCC,*r. Lab 6: Measurements of Liquid Density and Molarity -

Activity 2: Correlating Density and Molarity 2.1 Preparation of Standard Solutions Standard Solutions 0.15M 022 M 0.30M Target mass of sugar VA o V& = 2. (’,‘3 (calculated in the pre-lab; confirmed by the TA) Actual mass of sugar Lo R e . 2R 4 _3_;:%{._\% (record exactly what was massed; should be close to the “target”) 9 Volume of solution 25.00ml B5ComL Sbaomi Actual molarities: QAN ONRAHGM QRN (show all calculations) \.03\8® o 3W3. 2o OOOIBENSR _ | e S.035 \.STNe 0P UGHOTIIN | 4y \ae\uaE e AR 30, OO 3086\ ©-0ONSTNAEC | o 2 g m\oaEq 3L\'a_‘3®% ' o . 025 ) 2.2 Density of the Standa'rd Solutions Standard Solutions 0.15M 0.22 M 0.30M Mass of empty beaker .2.8&&58% a&_fififl_&g m&_& Volume of solution pipetted 10.0n o) Mass of beaker and solution 3&5.00&5 &EQB_B:.\ L\_\Qaaaa Mass of solution AQ_.D_?J‘jE% Q .0\'-\'26(3 A Density !.Qf:elml_ Q-8 %} mL Lo\d o L (show all calculations) ) , \0.021 B T N, B, .o N oa ——— > 0.aaal 36 \O.O0O mL / Lab 6: Measurements of Liquid Density and Molarity 5

Lab Report 6: Liquid Density and Molarity Name y;em’ (‘nrr\e;? Partner Apacapenes Lab Section _ ¢ 2.3 Draft Calibration Plot of Molarity and Density Prepare a fully labeled plot of actual density (x) and actual molarity (y). Draw in a line of best fit. Title: M\Q\- af \"\G\O\f‘\\'\: o) ‘De(g\\’\’ o%n O o5 O3 O3 05 o35 OY RO Mohere vy (Y Lab 6: Measurements of Liquid Density and Molarity 75

La : : b Report 6: Liquig Density and Molarity Name Jhe ly COCOENS artner A.\hn\‘r‘\\ o Lab Section _w.\ —— —— ————— Activity 4. ty 4: Software-Generated Calibration Curve and Results Prepare angd attach atio ; a software-generated cal below, write the equation of the fit lin H calibration graph. In the space A 3 X € as given by the software. Then re-state the equation using “density” and “molarity instead of Y- - N=0.0503 « 02l %- 0.500\ Molari rity of Sugar (calculated from the equation for the best-fit line — show all work): Beverage 1: 1= e.08a (oY 0.a9% Nz \.QL\—,\_ Beverage 2: N=0.0203 (0.9~ 6.9 Y= \.ony Post-Laboratory Questions 1. If, unbeknownst to you, the balance you used was not correctly calibrated and the actual mass of sugar added to your flask was less than what you recorded, how would that have affected your molarity - i.e., would it be higher or lower than what you originally calculated, and why? AL we oolonce oS N\OY C¢><‘<‘cc)-\\, CoNotor e oA Xae OCHLC) MO ©F oo odded YO vne L\CaW coos S o oONeT (oo eCorded, e molacihy covd VC waper ¥aoun (OROX WS oaQuaoNNy Cedtul\ahed. TR @ 0elfodde ¥re COTeCh OnmooNT ot So%ox' Loom aor OAAEA. oA Tnerefore Bre Colculaianyg were 0k - 1.6 oSS ord ooy owe difee My R\oXed, oS one incleoSey SO doel, e ovWner, 2. Compare the molarity of sugar in the beverages obtained from the draft calibration curve and the software-generated calibration curve. Which method do you think gave the better result and ? WX;{ Lo oKe - %e(\exo’?% coNNooRAn Corve apve Sne perec eS0\x, 0efauSe W B MMOfe OCLOONR o QesODe . Tre AEXx CoXoion CoMNe & Mhore ot on eSX.mare ord Nie\dS crofe @SN o u@(. Lab 6: Measurements of Liquid Density and Molarity

3. Comment on the accuracy of the calculated density of the standard solutions if a 50 mL beaker had been used to dispense the required 10 mL of water rather than the volumetric pipet - i.e., if you had used a 50 mL beaker to measure out the water, how would that affect the accuracy of your results? S o YO ¥ COM?O-‘; Do ofF Yl e praran CorNes, UDirey o BOmL veehed YO CreoSo e oOY e (equrifed \OmlL of (oo wnexead ob A k (oc. Volumexti& igex \goNes mole (eoWn for er CSita, & BomL veoNer oL\ e o exnnoke, Wrnecea on froex A oM Caly enSu(es WO Ml W\ pe (reasoced. R 4. Using the molarity you calculated for one of your beverages, find the grams of sugar in 355 mL of that beverage. (355 mL = one 12 fl oz can). Molar mass of sucrose: 342.20 g sucrose/1 mol Y= & 25 555l — 0. 3850 OV- O.BBT = O-BDO- ~o\ =O. 22D - oA ID A = AR oy ~_\,?_°‘La %:“\'8\. =\R Lab 6: Measurements of Liquid Density and Molarity