Question

1) A standard Beer's law graph of complex lon concentration (2 SF) versus absorbance (3 SF) was prepared and the equation describing the straight line is reported through Excel to be: A 11875 C (A: absorbance, C: concentration, M) Next, the following data was gathered in order to determine the Keq for the complex lon formation reaction. Calculate the value of K (6 pts) Stock sin [SCN'] 0.0023 M Stock sin (Fe") 0.0023 M A117750 Absorbance (complex ion) K11876 0103-11150 C-137-10-5 SCN mL HNO Fe Trial mL mL 1 1.00 5.00 1.00 0.163 2) An octahedral complex lon forms when some solid copper(I) nitrate, Cu(NOs)2 is dissolved in water. Upon addition of sodium cyanide, NaCN, a new complex ion forms after ligand replacement. Write a balanced equation for the ligand replacement reaction as described and show the Krvalue. Note: select a likely product based on your table of constants (2 pts) It is desired to collect 75 mL of hydrogen gas using electrolysis of a 0.55 M solution of sodium sulfate. Assume that the collected gas is saturated with water vapor at 30. "C and the collected gas pressure is 715 torr (mmHg). A power supply was used and set to 12.5 volts at a constant current of 3.5 A. How long (min) will it take to collect the gas? Assume that water has a saturation vapor pressure of 32 torr at 30. °C (6 pts) Show the balanced cathode equation: +e>N cafend

Answer 1

The ab soi bance Concentabion equoabion obser ved klaos: exs A 181S c dtae compley Pollas Given thak iS O163 absonbance the Concentraion Calculabe O163= 118Sxc C2 163 137X 16S M Jgns olotion andvolume osed Concentralion $tock iS Jiven GS O0023 M 0'0023m voA used-1-bo ML vol-used 100 mL volume (mx Concentralion () Toltal volome (m) vol.d S CN- vol.d H Total volomC Vol. dFe3L 10Om 14 5mltlc0mL 7.comL

O'00 23 M XIomL 3-29X16-4 ToomL a.o023 M X10ML 3.29x 10-4n Fe3 (on) Ca4) Fe scs4 t&N 37x 10-5 126.5 keac 126-S Ans t 2NO 4 CN +6H20 ey Cu(o t4CM CU the ke Now Lhe Pioduck value wil be ke, and kf

3ANS olakion t on soy dype a 9Vneous clect roy of tn AL Catho de Reduckion Among Nat Since Reduckon Nat anch H2a difeiculk in to sater starand Redocin Pokenkial to&dium in Companisi on iS high because water in Compar 33 m cathode and Pom ga H2o wiondergo yedocin at H2 4201 Ht 20H PH 715-32 638 forr 683 atm C4 atm 760 foY 09 L atm (304213) k- 303k 30 c- 75 X10 L V25ml

&Mydrogen gas moles Rgas Canstant nPu L at m mol Tb89.0 moles dH2- o99815xJ0 mol- 24.81 O.0821x 303 2-71x1mo mass d m, z molx mole colan mals 2.77 X-10 x2 5-121 16 8 uS st ao dforada fe electroly sis wEwxTy w: weisht dt H Eusi valent wght 5.42x 16 6 Soo Corrent 3 SA EwxI IX3.S b Lime lseconds) Faraday Constank-s 523 03 nds 3.S 149.43 Second ILa.13inute 2.49 min