Australia's Science Forum

HI all,
I have finally had my chemcal storage containers delivered so now I can start filling my chem store with standard solutions so I was just wondering what concentraitions everyone keeps stocks of for say HCL, H2SO4, NaOH or even what pre made stocks you keep?
Cheers
(reminder that im new to school work and the school im at is new to)

Hi, I try to keep 2.0M - 1.0M - 0.1M then if I'm out of 0.1M I can quickly make from 1.0M and so on. Hope that helps. Have a good weekend.

HCl, H2SO4, HNO3, & NaOH - 0.1, ,1,2, (have a fair bit made up 2L plus some 500ml and 250ml containers of each.) 0.5m (a couple of 500ml ) and 4 & 6m - 250ml. I don't have as much HNO3 made up as we don't seem to use as much of this, but still have the variety.

It has all been governed by demand over the years. But with the basic made up, you can dilute to make up what you need in a hurry. Remember to be careful with H2SO4 as it gets hot and takes a while to cool. Have fun!

Thanks for that ,now i have something to do next week! have a great weekend!

Hi Rowan, I'm sure I'm probably making more work for myself but because we have small classes I just start from scratch each time. Although I have some 'leftovers' but generally 0.1M of NaOH & HCl.

As well as 2L of 1M and 0.1M of the acids and NaOH, I have a small container of 4M of HCl. and H2SO4 .. for emergencys when a teacher suddenly asks for 4L of 1M or such...

I have a winchester (2.5 Litres) of 1M of Sulfuric, Hydrochloric, Acetic and Nitric Acid and Sodium Hydroxide in each of my 3 prep rooms as well as a winchester of 4M of each in the Chem store so I can make up a 1M at a moments notice.

At certain times of the year I can go through several winchesters of Hydrochloric Acid and Sodium Hydroxide each week.

There are also a couple of 500 ml bottles of more dilute acid and base solutions that are made up as needed and then kept until they are empty.

Most of my other chemicals ( eg copper sulfate, Lead Nitrate) are made up in 0.1M and 1m solutions in 500ml and 250 ml bottles. I also have class sets of 10 dropper bottles of 0.1 solution in a large variety of Nitrates, sulfates, chlorides and carbonates for precipitation and other pracs.

I keep winchesters of 6M HCl, HNO3, H2SO4 and CH3COOH plus NaOH and dilute from there. We use a lot of HCl so I keep 2 winchesters of 6M. Also keep 2M, 1M and 0.1M winchesters of these solutions too along with 250/500mL bottles and dropper bottles of each on the shelf.
For things like Pb(NO3)2, AgNO3, KI, BaCl2, Zn(NO3)2, CuSO4, NH4NO3, Na2CO3 etc., I keep a litre of 1M on the shelf to dilute to winchesters of 0.1M as needed. Most of these 0.1M solutions are in dropper bottles and 250/500 mL bottles on the shelves too.
Cheers,
Fran

Morning,

Hope you all had a wonderful longweekend, mine was too short as usual, but at least we had some lovely weather

To those of you using winchesters, from someone who is a little clumpsy (understatement of the year).... I hate using large bottles. Do you have any tips on safe handling etc, teachers want me to get some, which I think is a great idea as I wont have to make up chems all the time, but the size of the bottles make me sooooo nervous... I mean I am the type of person who trips on flat ground

Sass

Q-stores item number 2531461 single bottle carrier $31.15 or a 1970275 double carrier $33.37.

May help you be less worried.

I use plastic 2.5l bottles - gerry can style. They are lighter and with a handle, so much easier. BUT... I am running low on stocks, and can't see them in Q stores anymore. ANY plastic bottle is more comfortable and easier to transport, (if you can find them.)

The ones i just got are plastic they have a tap and another screw cap for filling they have a handle too very handy they hold up to 5 litres and are manufacutred by Deco but i got mine from an educational supplier

See the School cleaners, they often get chemicals in 4 or 5 L containers with tap, I use as distilled water bottles in each lab (9)

I keep 4M, 2M, 1M and 0.1M of the acids and 1M and 0.1M of most the other frequently used chemicals. I keep them in 2L plastic bottles I got from the hospital (for 1M or less - see photo in another thread) and winchesters for the others. I don't need to carry the winchesters far (bench - cupboard - bench...) and the stonger acids don't come out that often anyway. I tend to make up the hydroxides when needed because they just seem to go flakey in the bottles after a while. Does anyone else have that problem?

Yes I have that problem with hydroxides too and have decided not to make up large amounts any more.

If you are looking for 1 L plastic containers (with a handle) or 2 L ones, Serrata stock them.
I don't like carrying heavy glass containers either. I feel very much safer with plastic. I find the 1 L ones are great for using in the labs and they are usually large enough for most classes.

Robbie

Over the years I have learned to carry Winchesters by having one hand under the base of the bottle and the other hand on the neck. I feel perfectly safe doing it this way. Even getting the bottle out of store before putting it into a safety carrier it is important to carry it correctly.
Regarding kept solutions; hydroxides should really only be made as required. Not only do you get flakes but the solution also loses it molarity.
Maree

If solutions of NaOH lose their molarity over a period of time, do stock solutions of acids also lose their molarity?
Lyn.

How long do the Hydroxides last??????????? I have some here that were here when I started.

A 4M Sodium Hydroxide it would be about 6 years old?????????

I don't think it is that they 'lose their molarity' as such, but more that it comes out of solution. The same number of moles are still in the bottle, but it is in solid form stuck to the sides of bottles or in flakes on the bottom. Gived it a shake and see if you have a clear solution. You can probably filter them and then standardise them by titration using oxalic acid to find out exactly what the current molarity is if you want. Otherwise, this is school science, so I wouldn't worry too much - just make up senior stuff fresh and use up the others on the juniors.