Hi all,
I've only been a science school assistant for 4 months and I am still finding my feet in this challenging enviroment. I am the only technician at our school and the previous assistant had left before I started.
Previously I worked for 16 years in Pathology lab as a Medical scientist. I am finding that even though I have some general science knowledge, my previous experience was such a specialised field that I'm challenged every day with ordinary things. eg. molarity of solutions, and definately physics.
I'm finding this web site very enlightening and look forward to learning a lot more from colleagues who have been working in the field for a long time.
My question is:
Does anybody keep a supply of bulk chemicals available to use eg: 1MmHCl etc. ?
If so what chemicals and what quantities??
Thanks for you help.
Lorrae
Bulk Solutions
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Dee
- Posts: 55
- Joined: 01 Jun 2006, 10:00
- Job Title: "Second in Charge"
- School: Gosford Selective High School
- State/Location: NSW
Bulk Solutions
HI there,
I am glad you are finding your feet. My background is Industrial Microbiology and I found it a bit daunting at the start too. I have worked in the school system for about 7 years now and really enjoy that every day is different from the day before.
My school is seniors (11 + 12) only so it is a little different from a 7 to 12 school.
I do have some bulk supplies of basic acids, alkalines as well as some of the more common solutions we us. I usually only have 1 to 2 litres as I like to make solutions up fresh as it is ordered.
A lot of our solutions are also kept in dropper bottles so I tend to make these up as needed.
I am with you as far as the physics stuff is concerned - it is still all double dutch to me
Hope this helps
Dee
I am glad you are finding your feet. My background is Industrial Microbiology and I found it a bit daunting at the start too. I have worked in the school system for about 7 years now and really enjoy that every day is different from the day before.
My school is seniors (11 + 12) only so it is a little different from a 7 to 12 school.
I do have some bulk supplies of basic acids, alkalines as well as some of the more common solutions we us. I usually only have 1 to 2 litres as I like to make solutions up fresh as it is ordered.
A lot of our solutions are also kept in dropper bottles so I tend to make these up as needed.
I am with you as far as the physics stuff is concerned - it is still all double dutch to me
Hope this helps
Dee
Like Dee I have Shelves of 1 Litre bottles of solutions ready for use.
Common ones Like HCl have 6M,3M,2M,1M x2, 0.1M x2 & 0.01M
But all this would depend on usage/ your No of students
I have 1150 students in YR's 11&12 in our school so often have 2 classes doing prac at same time.
Best idea is to carry on as you go leaving labeled bottles on shelf till you get a feel for whats needed.
Common ones Like HCl have 6M,3M,2M,1M x2, 0.1M x2 & 0.01M
But all this would depend on usage/ your No of students
I have 1150 students in YR's 11&12 in our school so often have 2 classes doing prac at same time.
Best idea is to carry on as you go leaving labeled bottles on shelf till you get a feel for whats needed.
If you look in CSIS package, we are not allowed to give away chemicals & solutions as it makes us a supplier & subject to regulations covering transport & all its documents. Transporting chemicals in our cars also null & voids our car insurance. There is a great book called "The Laboratory a science reference & preparation manual for schools" by B. Dungey available from Southern Biological.
Bulk Solutions and Quantities.
Most School Laboratories and certainly those that have Yr 11 and Yr 12 will no doubt have a good stock of bulk solutions. It is much more user friendly to make these solutions in quantities of 1L to 2.5L at one time.
I try to make up my solutions in 2.5L Winchesters with various acids and alkalis in a range of concentrations.
I try to store these for no more than 2 years at a time to keep the concentration stable. Air changes the pH of the solution and can effect concentration ranges as CO2 is absorbed from the atmosphere, particularly with acids like H2SO4 and CH3COOH (this one more importantly).
NaOH has a good reputation for forming insoluble flakes upon prolonged storage after about 1 month if the solution is not constantly shaken.
If you require to check or standardise the solution to get an accurate concentration then this process is a little challenging and quantitative. But this way over time you can see how much the solution could be/is changing.
But apart from that I keep on hand quite a few solutions covering different types of acids and alkali’s at various concentrations.
I try to make up my solutions in 2.5L Winchesters with various acids and alkalis in a range of concentrations.
I try to store these for no more than 2 years at a time to keep the concentration stable. Air changes the pH of the solution and can effect concentration ranges as CO2 is absorbed from the atmosphere, particularly with acids like H2SO4 and CH3COOH (this one more importantly).
NaOH has a good reputation for forming insoluble flakes upon prolonged storage after about 1 month if the solution is not constantly shaken.
If you require to check or standardise the solution to get an accurate concentration then this process is a little challenging and quantitative. But this way over time you can see how much the solution could be/is changing.
But apart from that I keep on hand quite a few solutions covering different types of acids and alkali’s at various concentrations.
Last edited by Robb on 12 Jun 2006, 23:14, edited 2 times in total.
Dr Robert Crosdale. MRACI. NSS. NSSA. NASA.
Ph.D (Chem), Post Grad Ph.D (Physics), M.Ed, B.Sc (Hons), Dip. Appl. Sc. (Chem)
Lake Munmorah High School.
University of New England.
University of New South Wales.
University of Newcastle.
To understand the Universe from our perspective, we need to look towards our own backyard first for answers.
** AD ASTRA PER ASPERA - SEMPER EXPLORO **
Ph.D (Chem), Post Grad Ph.D (Physics), M.Ed, B.Sc (Hons), Dip. Appl. Sc. (Chem)
Lake Munmorah High School.
University of New England.
University of New South Wales.
University of Newcastle.
To understand the Universe from our perspective, we need to look towards our own backyard first for answers.
** AD ASTRA PER ASPERA - SEMPER EXPLORO **
I am also from a refinery laboratory background and the lab technician had left when I started so here I am about 18 months into working and still finding out what some of the equipment (especially physics) is for a start and then what it is used for.
I do have a question in regard to the storage life of chemicals. I have some items that were purchased in 1999. And then solutions that were made befoe I arrived. What is the best practise for the keeping time of solid chemcials and should I dispose of the solutions that I dont know when they were made?
A note in regard to the replacement of the solid chemicals, as we are a small school we dont consume a great deal each year which is why we have certain bottles of chemicals that have been here a long time. If some of them need to be disposed of what is the best criteria to judge what should be chucked and what is ok to keep?
I do have a question in regard to the storage life of chemicals. I have some items that were purchased in 1999. And then solutions that were made befoe I arrived. What is the best practise for the keeping time of solid chemcials and should I dispose of the solutions that I dont know when they were made?
A note in regard to the replacement of the solid chemicals, as we are a small school we dont consume a great deal each year which is why we have certain bottles of chemicals that have been here a long time. If some of them need to be disposed of what is the best criteria to judge what should be chucked and what is ok to keep?
Hi Nikki,
You may want to contact your regional technician in regards to your older chemicals etc. You can find out who your regional technician is by logging on to their website at rtg.wa.edu.au. This is a fantastic group of people who are always happy to help out when you need some help and answer any queries you may have regarding just about anything to do with school science labs and experiments. They are always up to date with the latest information. Good luck!!!
You may want to contact your regional technician in regards to your older chemicals etc. You can find out who your regional technician is by logging on to their website at rtg.wa.edu.au. This is a fantastic group of people who are always happy to help out when you need some help and answer any queries you may have regarding just about anything to do with school science labs and experiments. They are always up to date with the latest information. Good luck!!!
Hi Nikki,
Storage life of solid chemicals are fairly infinite, depending on a few factors though.
1. Whether the chemicals are contaminated, particularly from student use;
2. If there is moisture present inside the container or bottle.
3. Whether there is signs of deterioration or material breakdown (Discolouration other than from contamination).
These factors will render the chemical un-useable
But generally it is a good idea to check those you may have doubts with find any evidence of the above problems.
Other than that, there is no problem with storage times with any older chemicals.
Keep in mind that chemicals that are hydrated will contain moisture inside the container for obvious reasons.
As far as the diluted reagents go, depending if the solutions are used within around 2 years, or as long as there is no evidence of any contamination inside the container/bottle, then there should be no problem with these solutions. If a precipitate or other contaminant exists then the concentration may change. This is why solutions need a specific time frame for use.
Some insoluble material from reagents that have been freshly made fallout as a precipitate contaminating the solution inside the bottle/container. This happens quite alot to Copper (II) Sulfate, as this contains some limits of purity. (The precipitate is a Orange/Yellow colour).
Storage life of solid chemicals are fairly infinite, depending on a few factors though.
1. Whether the chemicals are contaminated, particularly from student use;
2. If there is moisture present inside the container or bottle.
3. Whether there is signs of deterioration or material breakdown (Discolouration other than from contamination).
These factors will render the chemical un-useable
But generally it is a good idea to check those you may have doubts with find any evidence of the above problems.
Other than that, there is no problem with storage times with any older chemicals.
Keep in mind that chemicals that are hydrated will contain moisture inside the container for obvious reasons.
As far as the diluted reagents go, depending if the solutions are used within around 2 years, or as long as there is no evidence of any contamination inside the container/bottle, then there should be no problem with these solutions. If a precipitate or other contaminant exists then the concentration may change. This is why solutions need a specific time frame for use.
Some insoluble material from reagents that have been freshly made fallout as a precipitate contaminating the solution inside the bottle/container. This happens quite alot to Copper (II) Sulfate, as this contains some limits of purity. (The precipitate is a Orange/Yellow colour).
Last edited by Robb on 16 Jun 2006, 23:41, edited 3 times in total.
Dr Robert Crosdale. MRACI. NSS. NSSA. NASA.
Ph.D (Chem), Post Grad Ph.D (Physics), M.Ed, B.Sc (Hons), Dip. Appl. Sc. (Chem)
Lake Munmorah High School.
University of New England.
University of New South Wales.
University of Newcastle.
To understand the Universe from our perspective, we need to look towards our own backyard first for answers.
** AD ASTRA PER ASPERA - SEMPER EXPLORO **
Ph.D (Chem), Post Grad Ph.D (Physics), M.Ed, B.Sc (Hons), Dip. Appl. Sc. (Chem)
Lake Munmorah High School.
University of New England.
University of New South Wales.
University of Newcastle.
To understand the Universe from our perspective, we need to look towards our own backyard first for answers.
** AD ASTRA PER ASPERA - SEMPER EXPLORO **
A word of advice about storage of NaOH solutions. Caustic attacks glass! That white precipitate you see in glass caustic bottles over time is a silicate from the glass. Store your bulk solutions of caustic in polythene bottles.Polythene Stull dropper bottles are available at $40 for 50 bottles. If you insist on using glass dropper bottles then empty them out and rinse them in between uses.
Wombat
Wombat
Hi guys and girls
I too am finding this forum useful and interesting. Thank you to all who've set it up and contributed.
I am also from a Med lab science background and even after 7 years in a K-12 school have my challenges. Hang in there guys. You do get a feel for things but I find that every year is different and each teacher has their own way of wanting things. Flexibility goes a long way.
A web site by NSW DET has useful info for physics equipment
How Things Work
http://www.curriculumsupport.nsw.edu.au ... ?u=3&i=119
Ellie Croft
Trinity Christian School
Canberra
I too am finding this forum useful and interesting. Thank you to all who've set it up and contributed.
I am also from a Med lab science background and even after 7 years in a K-12 school have my challenges. Hang in there guys. You do get a feel for things but I find that every year is different and each teacher has their own way of wanting things. Flexibility goes a long way.
A web site by NSW DET has useful info for physics equipment
How Things Work
http://www.curriculumsupport.nsw.edu.au ... ?u=3&i=119
Ellie Croft
Trinity Christian School
Canberra
