Australia's Science Forum

What do people use in their flame test kits, Nitrates or Sulfates & Chlorides??

I need to set up a kit.

Good morning again,
I use chlorides. Nitrates should not be used due to their toxic nature.
Maree

We use Chlorides and sulfates.. We don't use spray bottles any more. I soak toothpicks in distilled water and have the powders in petri dishes. The students use a toothpick to pick up a little of the powder and hold that in the flame..Mess free!

I use pop sticks that have been soaked in the solutions and then left to dry. Each popstick is labelled with the element they are testing. The kids love putting the popsticks in the bunsens and seeing the colour of the flame change. I also give them an unknown popstick they have to identify which gives them a purpose for the whole experiment. Of course if they leave the popstick in the flame long enough then it catches on fire.
The popsticks can be made months ahead so I always have a ready supply.
I use:
Barium chloride
Calcium chloride
Sodium carbonate
copper chloride and
potassium nitrate
though reading the earlier post, perhaps I shouldn't be using potassium nitrate??????

We've used spray bottles, pop sticks and wire loops dipped in the powder. The best and easiest is to soak pop sticks in distilled water overnight. Then, whilst wet, dip in the powders and into the bunsen. This way the sticks don't burn.

This came about by mistake. The teacher thought I could read her mind - which I've probably done many times - and her order was not very specific. So when I did all the pop sticks in distilled water, instead of soaking them in the various solutions, she was unimpressed, and I quickly told her, I'd improved the method. All she had to do was dip them in whichever salt and they won't burn! Thank heavens it worked.

This is an answer to Jen1. i also use Potassium nitrate, I found that Pot. chloride is usually contaminated with Na+ and gives yellow flame.
lada

Chlorides and sulfates. And I use the wet toothpick. One use only...saves cross contamination. Because the toothpick is soaked, works a treat!

Thanks lada.

Hmmm! I feel a bit out of it here! I have only been in the job 2 1/2 years and our Flame Test stuff was already set up by our then Chem teacher (who has a PhD in Chemistry) We have always used Copper NITRATE, Barium nitrate, sodium Nitrate, Ferric Nitrate, Potassium Nitrate, Lead Nitrate, Calcium Nitrate and Strontium Nitrate. I am pretty sure that they were all "Green dot" chemicals when in 0.1M solution. We have used spray bottles as well as soaking the paddle pop sticks in the solution, but the spray bottles have given us the best results.

Perhaps I had better investigate our supply of metal Chlorides for next year!

Cheers

Ian

Yes Ian.. maybe that was all they had available then? I had to use a nitrate in my kit for a while, until I had the Sulfate to replace it

sorry realise this is an old thread but i was reading it with intrest as the teachers here have decided to go back to flame tests since i suggested we try the soaking match sticks in the soln and then burn those - for those who soak their match sticks in the solution then burn what molarity do you soak in please.

thanks for the tip to on not using potassium chloride but the nitrate - i would not have thought about sodium contamination

Hi dolphinscales
I have a a saturated solution of each and keep them only for soaking pop sticks in for flame tests.
Havent tried match sticks, I would think that popsticks would be a bit easier.
Cheers
Jen
PS are you going to the regional meeting on thursday? If so see you there

The problem with wood sticks is that carbon burns with bright yellow flame that can confuse results

True, Ocker, once the pop sticks catch on fire they burn yellow, but we encourage the students to wave the pop sticks up and down in the flame and then they can see the colour easily. It's not a perfect method but we just dont trust the kids with spray bottles, we know they will be spraying each other with them. So we have found this the best method so far.

I use the methord where you insert bunsen in cut off softdrink bottle, with small window, spray into hole and then it mixes with air going up tube of burner, Works Brilliant!

Hi
I'm probably way behind the times but was reading the old flame test posts and discovered Ocker is using the same method as me with the soft drink bottle. It really is great and there is very little mess afterwards. Does anyone else use strontium chloride, thats my fave.
Krysia

Chlorides & sulphates. We use wire loops. Kids wet them & then pick up some chemical. Seems to work well.

Then I do a demo of some of the nitrates & Lithium chloride in the fume cabinet. Then they get their unknown x 2 to identify. Amazing how many don't keep records as they go...!

Yes we use the strontium chloride. So pretty.

Rita

I am curious about the soft drink bottle method? I am having visions of a melted blob of plastic over the bunsen.
At the moment I am using pop sticks but am open to new ways.
Cheers
Estelle

I will try to paint a word picture
Cut a 1.25 L bottle just below half way insert bunsen burner till it sticks out neck mark where gas spout is and cut hole for gas tube then cut a window in side level with air holes the bit you cuyt off can be inverted and placed in bottom this seals and supports burner up in bottle spray small fine mist into window it mixes with air and goes up the burner stem then burns with distinctive colour I usually set up 6 or 7 around and have kids spray same salt soluiton in the burner then move to next one for next salt to avoid contamination
Is that Clear?