Lab 3.1 Determination of the Solubility Product Constant of Silver Acetate

CHEMISTRY Lab 3.1: Determination of the Solubility Product Constant of Silver Acetate Purpose: to determine the Ksp of silver acetate in a displacement reaction. The Ksp of AgCH3COO can be determined by allowing a saturated solution of the salt to react with copper in a single displacement reaction as follows: + +2 Cu (s) + 2 Ag (aq)  Cu (aq) + 2 Ag (s) The three solutions were prepared as follows: Solution 1: 0.100 M AgCH3COO Solution 2: 0.200 M AgNO3 mixed with 0.200 M NaCH3COO Solution 3: 0.300 M AgNO3 mixed with 0.300 M NaCH3COO Procedure: DAY ONE: 1) Carefully measure 100. mL of one of the saturated solutions of silver acetate (the teacher will assign one solution to you) in a 250 mL beaker or Erlenmeyer Flask 2) Measure a 30 cm length of Copper wire and obtain its mass 3) Coil the Cu wire and suspend it in the silver acetate solution, leaving it to react overnight. DAY TWO: 1) Shake the silver off the wire. Clean it under a stream of water (be frugal with the amount of water rinsing), being sure to collect all washings in the beaker (NO SILVER DOWN THE DRAIN!) Rinse wire with acetone (a tiny amount) and let it dry. Record the mass of the dry wire. 2) Filter the rinsings beaker through a filter paper, into another beaker. Give the contents of the filter paper + solid to the teacher for silver recovery. The filtrate liquid must be poured into a separate container at the front of the room.     ***STAPLE THIS PAGE TO THE BACK OF YOUR LAB REPORT*** You will submit a lab report that includes everything listed on THIS side of the page: Observations: record qualitative observations as usual Data: Include temperature, volume of solution used, mass of Cu wire (before and after), mass of Cu reacted, concentration of Cu+2 standard used. Include uncertainties and units whenever applicable. Calculations: 1) Find, from the missing mass of copper, the moles of Cu (s) that reacted with the silver. 2) Using the balanced equation given on this handout, determine the number of moles of Ag+ (aq) that reacted, and its concentration in the saturated solution. 3) Using a balanced dissociation equation for silver acetate, find the concentration of acetate ion in the saturated solution. 4) Calculate the Ksp of silver acetate. 5) Compare your Ksp value to the Ksp of groups who used solutions different from yours. What can you conclude from the comparison of the 3 values? Calculate an average of the 3 Ksp values that you have collected and calculate your standard deviation. 6) The accepted value for the Ksp for silver acetate is 4.0 x 10-3. Find your % error relative to this value. Questions: 1) State two reasons for this lab error in the Ksp value (from Calculation #6) 2) State two sentences (minimum) that link this lab activity to the theory we are currently studying. AVOID saying “we are learning about…” or “this lab relates to our notes because…” or “this is relevant because…” Try to write this as a mini introductory essay paragraph that introduces the concepts that allowed us to complete and understand this lab. 3) Propose another method for determining the concentration of Ag+ (aq) in the saturated solution. 4) Why is it important that there be no silver acetate crystals in the 100. mL of solution reacting with the Cu (s)? 5) If 100. mL of 0.0200 M AgNO3 and 100. mL of 0.0200 M NaCH3COO were mixed, would you expect a precipitate to form? Use the average Ksp value from Calculation #6 for this question. NOTE: Not required for this lab: Sources of Error, Discussion, nor Conclusion, as all three of these sections have been included in the calculations and questions. ***STAPLE THIS PAGE TO THE BACK OF YOUR LAB REPORT***