I\'m so confused on this. Can anybody please help me..? Thank you! Part II (Seco
ID: 492998 • Letter: I
Question
I'm so confused on this. Can anybody please help me..? Thank you! Part II (Second Lab Period) Goal #1: Isolate the liquid above the precipitate for each solution. You need to set up a filtration apparatus. Unlike the filtering you did in Part I of this experiment, this time you are interested in collecting the liquid not the solid. So will do a gravity you filtration. Set up a gravity filtration apparatus (see the skills document for information). Use fresh filter paper and a clean dry funnel for each solution. Do not wet the filter paper with DI water. Carefully pour the solution through the filter. Collect the filtered liquid (ie., the filtrate) in a clean, dry, labeled 50 mL beaker or Erlenmeyer flask. You need at least 25 ml of each solution, so be careful. Keep the same labeling system as before (e.g., the #1 filtered solution should be from the #1 reaction mixture). Slowly transfer all of the liquid then, all of the solid, to the filter funnel. When the filtration is completed, the solid Ca(IO,2 and filter paper should be transferred to the chemical waste container on the back balance bench. Give the labeled beakers or flasks containing the filtered solutions to the part of your team performing the titrations as they become available. Goal #2: Determine the aqueous concentration of IO3 in each sample by titration. Molarity Formula Quantity Name Determined Na2shoaae) Sodium Thiosulfate 250 mL in Part I 10 scoops using the Potassium lodide spoon provided in r kit Hydrochloric Acid t 25 mu 1.0 M HCI Starch Solution 10 mL 0.20% Fill the buret with the thiosulfate titrant. Drain some titrant out until the level is a milliliter or so below 0.0 mL. Make sure you don't have a bubble at the bottom stem of the buret (below the stopcock). Carefully pipet 10.00 mL of your solution "A1" into a clean 250 mL Erlenmeyer flask. Add 10 20 mL of deionized water. Add 1/4 teaspoon (1 scoop using the white spoon provided in kit of solid Kl Add 3 ml of 1 M HCL. Swirl to mix. The solution should be a dark yellow-brown color.
Explanation / Answer
Here all the calculations are mentioned.
The conclusions can be given as follows:
1) The equillibrium constant expression based on given data can be given as: K = [Ca+2][IO-3]2
2) As it's given in the description, the correct rate expression will give least scattered average/range value.
After observation, the least value obtained is for the option d. So that correct rate expression will be K = [Ca+2][IO-3]2
3) Based on the reaction the theoretical expression would be K = [Ca+2][IO-3]2 / [Ca(IO3)2]
But experimentally found expression is K = [Ca+2][IO-3]2. So both the rate expression don't match.
4) If you observe that with starting same [Ca+2] concentrations, the final solid concentration is different for solution B1,B2,C1,C2,D1,D2; except for A1,A2. It means that solid contribution Ca(IO3)2 towards equillibrium constant is zero. So that option a is ruled out.
5) The value of experimental equillibrium constant is K= 3.62*10-6 M