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Re: LEAD NITRATE

Posted: 05 Mar 2021, 13:22
by Milo
We swapped out our dropper bottles for 0.002M solutions. Precipitation pracs are next week so I'll report back if they work.

Re: LEAD NITRATE

Posted: 05 Mar 2021, 13:57
by J.Speaks
That would be great, thanks Milo! =D>

Re: LEAD NITRATE

Posted: 05 Mar 2021, 14:18
by Milo
We did an early trial to make sure it worked, and there was indeed a bright, immediate reaction between potassium iodide 0.1M and lead nitrate 0.002M. Perfectly viable in my view. :)

Re: LEAD NITRATE

Posted: 05 Mar 2021, 14:28
by J.Speaks
Nice! Looks like I better get to work diluting all of our stock, thanks for checking on that Milo! :thumbup:

Re: LEAD NITRATE

Posted: 08 Mar 2021, 07:14
by Merilyn1
I've offered the more dilute form to teachers and they seemed a bit unimpressed, without even trying it out! Occasionally, one will do it as a demo but not often. I'm happy, because regardless of what the students get to use, I have to handle the solid. I haven't had to make up new solution in years.

Re: LEAD NITRATE

Posted: 08 Mar 2021, 08:51
by Anna Z
If you get a reaction and change with the more dilute solution...I'd just put it out and not say anything to the teachers in future. If anyone gets agro...just plead the safety line :)

Re: LEAD NITRATE

Posted: 08 Mar 2021, 09:28
by Merilyn1
Anna Z wrote: 08 Mar 2021, 08:51 If you get a reaction and change with the more dilute solution...I'd just put it out and not say anything to the teachers in future. If anyone gets agro...just plead the safety line :)
Ha - they don't get agro, more just disappointed - kind of like if I'd told them the college has banned cake. :?

Re: LEAD NITRATE

Posted: 08 Mar 2021, 12:23
by Anna Z
Merilyn1 wrote: 08 Mar 2021, 09:28
Anna Z wrote: 08 Mar 2021, 08:51 If you get a reaction and change with the more dilute solution...I'd just put it out and not say anything to the teachers in future. If anyone gets agro...just plead the safety line :)
Ha - they don't get agro, more just disappointed - kind of like if I'd told them the college has banned cake. :?
:cheesy: that made me laugh a lot :)

Re: LEAD NITRATE

Posted: 07 May 2021, 10:58
by RosalieL
I've been asked for "at least 100ml per group" of lead nitrate and potassium iodide. I will make up 0.001M lead nitrate but that is a lot, right? I will talk to the teacher to see if they can reduce it to 10ml per group (or ask if it was a typo?) and get the same outcome (conservation of mass - yr 9). He's currently on class so I can't check right now. Also, the potassium iodide is meant to be used in a fume cupboard according to risk assess. Would you give out those quantities? We have 50ml dropper bottles, so would you just send out a stock solution bottle for them to pour into beakers?

Re: LEAD NITRATE

Posted: 07 May 2021, 11:12
by Merilyn1
That is a ridiculous amount! No they are not getting that much. Do you have spotting trays? (Ceramic tiles with small wells). With these they only need a few drops of the chemical.
We have given up using lead nitrate. I am so pleased, because although we worry about what the students handle, no one stops to think that we have to handle the solid!

Re: LEAD NITRATE

Posted: 07 May 2021, 11:14
by emma.hunt
Too much in my opinion.
Definitely in droppers for sure and spotting trays

Re: LEAD NITRATE

Posted: 07 May 2021, 11:39
by RosalieL
OK so after clarifying with the teacher he will need 100ml for the 2 classes! Not each group. All good! :thumbup:

Re: LEAD NITRATE

Posted: 07 May 2021, 12:02
by bigmack
RosalieL wrote: 07 May 2021, 11:39 OK so after clarifying with the teacher he will need 100ml for the 2 classes! Not each group. All good! :thumbup:
Great , so now you'll only have 200mls of heavy metal waste to deal with :D

Precipitant of Lead Nitrate and Potassium Iodide is white .It won't show in a spotting plate well .

For Precipitation pracs , I now draw up a word doc and print it onto overhead Projector sheets .
When placed on the black Lab benches , the colours show very clearly .Only drops needed not ml's of solution and no test tubes to wash afterwards .
precipitaion sheet.jpg

Re: LEAD NITRATE

Posted: 07 May 2021, 12:12
by RosalieL
It's for conservation of mass though, not just precipitation. They must be weighing it before and after. Love the table on OHP sheets though!

Re: LEAD NITRATE

Posted: 10 May 2021, 11:01
by Lyn
Lead nitrate and potassium iodide makes a bright yellow precipitate. Instant gratification and spectacular result. Silver nitrate and potassium iodide makes a white precipitate. Not as spectacular. We use sodium hydroxide 0.1M and copper sulfate 0.1M for conservation of mass practical. We are using the Pearson Science 9 textbook.