t 46% 3:18 PM facweb.northseattle.edu ..il Sprint CUT HERE Procedure I) NaCI (s) Bà Na+ (aq) Ci- (aq) (1) Add few drops of conc. HCI to 2 to 3 mL of saturated NaCI solution. AAWhat is the stress and which direction should the equilibrium shift? II) NH4CI(s) Ba NH+ (aq)+ CI-Haq) (2) Add few drops of conc. HCI to 2 to 3 mL of saturated NH4CI solution. III) Fe+3(aq) SCN-(aq) Ba Fe(SCN)+2(aq) (3) Prepare a stock solution by mixing 2mL each of 0.1M FeCI3 and 0.1M KSCN in 100mL graduated cylinder. Add enough water to make 100mL solution. Note the color. If you are the first one to use this station, make this solution and save it for the rest of the class. If you are using someone else\'s stock solution, make sure to make observations of each reactant (4) Add about 1mL of 0.1M FeC13 to about 5mL of stock solution. (5) Add about 1mL of 0.1M KSCN to about 5mL of stock solution. AAWhat is the stress and which direction should the equilibrium shift (6) \"Add 0.1M AgNO3 DROPWISE (less than 1mL) to about 5mL of stock solution until almost all the color is discharges. (The white ppt is a mixture of AgCl and AgSCN.) Split the solution into two test tubes including the precipitate. (6a) Add 0.1M KSCN dropwise (about 2mL) to one tube (6b) Add 0.1M FeCI3 dropwise (about 2mL) to the other tube IV) 2Cr04 -2(aq) + 2H+ (aq) Bà Cr207-2(aq)H20(U) (7) \"Add 2 drops of 6M HNO3 to about 3mL of 0.1M K2Cr04. AAWhat is the stress and which direction should the equilibrium shift? (8) Add 10% NaOH to (7) dropwise until the original color of K2Cr04 is restored. (9) \"Add 2 drops of 6M H2S04 to about 3mL of 0.1M K2Cr04 (10) Add 10% NaOH to (9) dropwise until the original color of K2CO4 is restored.
I) NaCl(s) --> Na+(aq) + Cl-(aq)
when few drops of HCl was added
HCl(aq) ---> H+(aq) + Cl-(aq)
It increased Cl- concentration in solution, therefore according to the LeChatellier\'s principle, more of Na+ would not combine to form NaCl, and this would continue until all of th excess Cl- is consumed and equilibrium is resestablished again. The reaction thus would shift to the left handside.
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II) NH4Cl(s) --> NH4+(aq) + Cl-(aq)
when few drops of HCl was added
HCl(aq) ---> H+(aq) + Cl-(aq)
It increased Cl- concentration in solution, therefore according to the LeChatellier\'s principle, more of NH4+ would not combine to form NNH4 and this would continue until all of th excess Cl- is consumed and equilibrium is resestablished again. The reaction thus would shift to the left handside.
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III) Fe3+(aq) + SCN-(aq) <==> Fe(SCN)2+(aq)
(3) stock : 2 ml of 0.1 M Fe3+ and 2 ml of 0.1 M SCN- diluted to 100 ml
color deep red.
(4) add 1 ml of 0.1 M FeCl3 : color darkens
(5) add 1 ml of 0.1 M KSCN : color darkens
(6) 0.1 M AgNO3 to 5 ml stock : color disappears [forms Ag(CN)2^- colorless]
(6a) add 2 ml of 0.1 M FeCl3 : reformation of red color [forms [Fe(SCN)2+]
(6b) add 2 ml of 0.1 M KSCN : reformation of red color [forms [Fe(SCN)2+]
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