Alternative to lead iodide + potassium nitrate

Discussion in 'Science Technicians - General Discussion' started by Techitude, Jun 14, 2019 at 10:21 AM.

  1. Techitude

    Techitude COMMITTEE

    We have a practical from AQA that involves students weighing small amount of potassium iodide and lead nitrate, mixing them together, filtering the lead iodide then reweighing it.

    It's a good practical in principle but the students dont stick to the instructions and we are having large amounts of product coming back and finding it all over the lab benches and in the sinks which obviously isnt ideal at is lead iodide.

    I've suggested they substitute it for copper sulfate and sodium hydroxide perhaps but does any one have any better alternatives?
     
  2. Copper sulfate + sodium carbonate to give copper carbonate (insoluble) and sodium sulfate?
     
  3. Techitude

    Techitude COMMITTEE

    Ah good thought, forming basic copper carbonate hydroxide. Only issue is that the students are asked to write a balance equation for this and I think it will be too complex for them as you need to include the water and carbon dioxide on the respective sides to get it to balance.
     
  4. Isn't that quite an easy equation to balance?:)
     
  5. up-scale the sulphate test (white ppt. with barium chloride) to filter off the barium sulphate should do the trick.
     
  6. The balanced equation for what I listed is CuSO4 + Na2CO3 --> CuCO3 + Na2SO4
    It's already balanced as is which is convenient ;)
     
  7. I see what techitude is saying, unless you're doing it without either being dissolved in solution then your equation should be:
    CuSO4 + Na2CO3 + H2O = Cu2(OH)2CO3 + Na2SO4 + CO2
     
  8. Fair enough, guess that makes sense.
     
  9. Techitude

    Techitude COMMITTEE

    Yes I was thinking you are more likely to produce copper carbonate hydroxide which is more complex equation, but I guess the teacher could just tell them it is copper (ii) carbonate to make the equation simpler.
    However, apparently they want an equation that does need some balancing, I may just stick to the CuSO4 and NaOH
     
  10. Iron (III) chloride and trisodium phosphate - or if you want to make them work Fe (II) sulfate and trisodoium phosphate