Question

LAB DATA The lab data shown below reflects what you would have collected during lab on campus. Use this "virtual lab data" to complete the calculations in this lab. Concentration (M) of starting solution .024 1st Reading 2nd Reading Abs (15-mL .024 M Cu2+ + 7 mL conc NH, diluted with distilled H 0 to 100 mL total volume) 0.945 0.923 Abs (5-mL .024 M Cu2+ + 7 mL conc NH, diluted with distilled H,0 to 100 mL total volume) 0.617 0.693 Abs (15-mL Unknown Cu2+ solution + 7 mL conc NH, diluted with distilled H2O to 100 mL total volume) .713 .713 Abs (5-ML Unknown Cu2+ solution + 7 mL conc NH; diluted with distilled H2O to 100 mL total volume) .404 404

Answer 1

lon. Based on the Beer's A = 6.c.& A absorbance E-mdar absorptivity ca molar concentration e-path length Absorbance for 15.0m 0.024 Men 24 A = 0.945 Ag= 0.923 Average A2 0.945+0.923 2 i. No. of moles of cu't in sohntion = 0.024 x 15 s 3.6x10h mole. [eu 2+ ] in 100 ml sohn 3.68104 lono a = 0.0036H Absorbance of 15m2 unknown cu? A1 = 0.713 A F0.713 A Avg A = 0.719 +0.710 2 0 .713 form the 1st Case I Enda c oooong - 269.44 Concentration of unknown Cult 0.934 & cafe - 25944 = 0.0027 M. e unknown stock sor Concentrale 100 me) x 0.00 27 H. 15.0ml = 0.018M ". The molarity of unknown en 24 is less than the standard stock soha

Absorbance his s.com curt A = 0.617 A₂ = 0.693 Average A 0.617 + 0.69 0.655 No. of moes of eit - 0.024 x = 1.24104 mole [euert Teuta 1.28104 - 1.2410 3M. from Beer's low. M. 1.2 X10 Oloo 72m 0.655. Eola 1545.83 1.2x10-3 Absorbance of unknown sinnen 24 21 A1 = 0.404 Az = 0.404 Ang A = 0.40u.. Molarity of diluted cu 24 (5ml) 10. You a = 7.40x1oM e 545183 Son Melanity of some en stock sok 1 7.40x10x100 ca c = 0.0148 M