Question

The first picture is used for question #2, and question #3 can be normally answered. I believe the answer to question 3 is -> 0.07144M. However I would like someone to check it. I am not sure about 2.

BE SURE THAT YOU RECORD ALL OF YOUR DATA AND LABEL PROPERLY FOR PARTI OF THIS LABORATORY EXPERIMENT. YOU WILL NEED TO ACCESS THIS INFORMATION IN THREE WEEKS. Part I Synthesis of the Complex Salt containing Copper Procedure 16.004 1. In a 250.0 mL beaker, weigh out approximately 10.00 g of potassium oxalate monohydrate, K2C2O4 H20 on the top loader balance and add 20.00 mL of distilled water. 2. Heat this solution, while stirring, until all of the potassium oxalate has dissolved. Do not boil the solution. Stop heating the solution when the solution becomes clear. 3. While the potassium oxalate monohydrate solution is heating, you can make your solution of copper(II) sulfate pentahydrate (CuSO4 5H2O). In a 250.0 mL beaker, weigh out approximately 1.00 g of copper(II) sulfate pentahydrate. Be sure to use the top loader balance and record the mass to the nearest or 0.01g. 4. Dissolve the copper(II) sulphate pentahydrate in 15.00 mL of water. 5. Pour the potassium oxalate monohydrate solution into the copper(II) sulphate pentahydrate solution. 6. Allow to cool to room temperature, you should see crystals forming. Let sit for another 15 minutes after the solution has cooled to room temperature. 7. Check your suction filtration apparatus as shown by your instructor. 8. Use a rubber policeman to scrape the crystals and solution into the funnel. If you have any crystals that remain in the beaker, wash them into the funnel with some 1:1 alcohol (ethanol)- water solution. 9. Rinse the crystals while they are in the funnel with 20 mL of a 1:1 alcohol(ethanol)-water solution. Pour this solution slowly so all of the crystals are washed. Pour 10 mL of acetone over the crystals making sure that it is poured over all the crystals. Allow to dry while suction is running for another 5-10 minutes. Weigh a clean, dry 250 mL beaker and record its mass. Use the rubber policeman to scrape the crystals off the filter paper and filter funnel into the clean dry beaker and place in your drawer. Do not cover the beaker. You will weigh the beaker with your crystals in two weeks. 2. Write the generic chemical formula for the coordination compound (complex salt) you made last week. (Do not write the chemical reaction. You will not receive any credit for writing the chemical reaction.) 3. When 0.1009 g of sodium cyanide is dissolved in solution, it takes 19.22 mL of a potassium permanganate solution to reach the end point of the titration. Using the balanced chemical equation provided, determine the molarity of the potassium permanganate. You will be doing a similar reaction in the laboratory this week. (Remember: the mole ratio of MnO4 to KMnO4 is 1:1 and the mole ratio of CN' to NaCN is 1:1) H2O (E) 2 MnO4" (aq) +3 CN (aq) 2 MnO2 (s) 3 CNO (aq) +2 OH (aq)

Answer 1

2 . Generic formula of the coordination compound formed is

K2[Cu(C2O4).2H2O] ,,,, This is the Cooper(2)oxalate complex with 2 water of hydration .

3 . No. Of moles of NaCN = mass/molar mass = 0.1009g/49 = 0.00206 moles of NaCN .

As chemical equation showed 3 moles of CN- reacts with 2 moles of MnO4^- , so no. Of moles required to balance 0.00206 moles of CN^- = (2/3) × 0.00206 = .00137moles .

So to balance the no. Of moles sodium cyanide at end point we need 0.00137 of potassium permanganate.

So no. Of moles of KMnO^4 = .00137 moles .

Molarity = no. Of moles/vol. Of solution in litre .

So molarity of KMnO4 = .00137/0.01922L = 0.00713 M

Your answer is corecor .