stock solution

Discussion in 'Supporting Chemistry' started by Jjoseph, Mar 14, 2019.

  1. Hi,
    Could anyone help me to prepare stock solution for rates of reaction practical please
    (sodium thiosulfate prac)
  2. Do you know what molar you need?
  3. We do that as the effect of temperature on reaction rates - use sodium thiosulfate 40g dm3 and 2M HCl with the following method:
  4. Is this for pag 10.2 for OCR with the 0.150M?

    I was going to make 1l of 1M and then just take 150ml of this and make it up to a litre, or have I done those calcs wrong?
  5. If you are doing the AQA required practical you need a 2M Hcl and a 0.25M sodium thiosulfate shown as 40g dm3. (Dissolve 39.52 and make up to 1ltr)
    Last edited: Mar 14, 2019
  6. Think thats the same as my AQA from what I can see rather than OCR
  7. They must be the same then as my page as OCR at the top of it :p
  8. Surely not ........that means they spoke to each other!!! :D
  9. Don't be stupid, they wouldn't do such a thing, they just both stole the idea from the same person.
    Dave T likes this.
  10. What we do and works perfectly every time:

    Sodium thiosulfate concentration: 0.05 M, amount per trial: 50 mL
    HCl concentration: 1M, amount per trial: 5mL
    Temperatures: 20, 30, 40, 50, 60 degrees celcius

    We do this in 100mL conical flasks which fit nicely in 400mL glass beakers as water baths.
  11. 0.15m sodium thiosulphate 37.23gm per litre this works well with either 1m or 0.5m hcl acid depending on teachers preferance also give them a carbonate bath to neutralise the sulfer gas given off
    Last edited: Mar 14, 2019
  12. Thanks for that David, saves me a dilution step :D
  13. It just means they all googled the experiment and picked the same one :p;)
    Techno likes this.