Australia's Science Forum

I totally get that its wrong and out of date but, my question was how have DET schools been labelling their Lead nitrate in the last 21 years ?

How have DET Labbies interpreted the CSIS info on it and used it to label their Lead Nitrate solutions ?

Sorry Richard - seems like we all went off on a rant. If, according to CSIS, the solid is 7-12 and the solution of <1% is also 7-12, wouldn't everything in between be 7-12? That was the path I took many, many moons ago when I had to use CSIS.
I'm no good with the maths, but Riskassess has 0.003 to 0.03M as equivalent to 0.1-1%.
Although, given the discussion, for the safety of students, I would be labelling 0.003 to 0.03M as 11-12 and <0.003M as 7-12, in accordance with Riskassess guidelines. I'd be telling management to jam CSIS in their chem store!

Cobalt Chloride and Nickel Chloride are another two that concentrations have been drastically reduced. I think if I was in a DET school I would be pushing for HT to get Risk Assess, I know a lot in our area are using it. Not just our safety but everybody concerned it's kept up to date, any questions they are only a email away and reply the same day. Couldn't get better service for the little amount $250.

Teachers get used to it.

Read the SDS. It's what I always do, just to double check, it's up to us to protect our own health and that of the students.. I have Risk Assess too. It has saved me sooo much time labelling.

Sorry to resurrect an old thread, but I just started as the Lab Manager at my school, and the prep room cupboards are filled with lead nitrate dropper bottles for student use for precipitate and replacement reaction pracs, but they're all either 1M or 0.5M, both of which are big no nos according to RiskAssess. The school just started using RiskAsses and I'm very safety conscious so I've taken it upon myself to come up with some alternatives.

For the short-term I've provided 0.05M Silver Nitrate for the labs that require precipitates and for the replacement reaction with KI. It's way more expensive than Lead Nitrate, of course, but it works and is safe for students 7-12 according to RiskAssess. Just make sure students wear gloves and lab coats as Silver Nitrate does stain your skin!

But my big question is what everyone else is doing about Lead Nitrate being used in pracs in their school? Does making a <0.003M solution (let's say a 0.001M solution since that's easy) still produce the same visual results that teachers want their students to be able to see?

We swapped out our dropper bottles for 0.002M solutions. Precipitation pracs are next week so I'll report back if they work.

That would be great, thanks 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.

Nice! Looks like I better get to work diluting all of our stock, thanks for checking on that Milo!

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.

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

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.

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.

that made me laugh a lot

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?

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!

Too much in my opinion.
Definitely in droppers for sure and spotting trays

OK so after clarifying with the teacher he will need 100ml for the 2 classes! Not each group. All good!

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!

Great , so now you'll only have 200mls of heavy metal waste to deal with

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 .

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!

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.