Best M.W. information

Request or contribute your recipes here. You can also try doing a search, as there are some old recipe posts which have not or cannot be moved over to this forum.
Post Reply
User avatar
kimmy
Posts: 418
Joined: 01 Jun 2006, 10:00
Job Title: School Lab Assistant
School: Quirindi High School
Suburb: Quirindi
State/Location: NSW

Best M.W. information

Post by kimmy »

OK i am doing up a new information booklet for the common chemicals i use at school. This is just for myself for making up solutions of my common chemcials.
So many sites have different information on them for the strength of chemicals.
What is the best site to get accurate information.
Even between the Working in Science book distributed to us from DET is different to the book "The Laboratory".

any suggestions will be appreciated.
:banghead2: :banghead2: :banghead2:
User avatar
J
Posts: 714
Joined: 13 Jun 2006, 10:00
Job Title: Lab Assistant
School: DHS
State/Location: NSW

Re: Best M.W. information

Post by J »

If in doubt, make your own calculations using the molecular weight of the chemical.
I have to rush off to a meeting now but I'm sure someone else can explain. Once you do this, you'll wonder why you ever had to look it up! :thumbup:
User avatar
kimmy
Posts: 418
Joined: 01 Jun 2006, 10:00
Job Title: School Lab Assistant
School: Quirindi High School
Suburb: Quirindi
State/Location: NSW

Re: Best M.W. information

Post by kimmy »

J wrote: 20 Aug 2020, 10:10 If in doubt, make your own calculations using the molecular weight of the chemical.
I have to rush off to a meeting now but I'm sure someone else can explain. Once you do this, you'll wonder why you ever had to look it up! :thumbup:
Yes i know how to do this but even these are different on different sites. I just thought someone might know a site where it was the correct M.W.
eg Ammonium Oxalate
MW on Pub Chem is like 124.1
but on another site it is
142.11
Merilyn1
Posts: 1476
Joined: 12 Mar 2013, 08:10
Job Title: Labbie
School: Wollondilly Anglican College
Suburb: Tahmoor
State/Location: NSW

Re: Best M.W. information

Post by Merilyn1 »

For molecular weight, check the individual container which will have it somewhere on the label, or, you can work it out from the formula, which will also be on the label. That would be the most reliable source.
bigmack
Posts: 816
Joined: 15 Dec 2015, 10:49
Job Title: Lab Technician
School: FCAC
State/Location: QLD

Re: Best M.W. information

Post by bigmack »

Anhydrous versions have different MW.
That is why it is best to use the MW on the bottle .That way you know it matches what you have .Some recipe books don't state which type .
tin chloride.jpg
You do not have the required permissions to view the files attached to this post.
User avatar
shellythenewlabby
Posts: 53
Joined: 01 Jul 2016, 12:17
School: Woonona High School
State/Location: NSW

Re: Best M.W. information

Post by shellythenewlabby »

Hi Kimmy
I usually use this website if i get stuck and have found it good. Hope it helps

https://www.sigmaaldrich.com/chemistry/ ... lator.html
User avatar
kimmy
Posts: 418
Joined: 01 Jun 2006, 10:00
Job Title: School Lab Assistant
School: Quirindi High School
Suburb: Quirindi
State/Location: NSW

Re: Best M.W. information

Post by kimmy »

shellythenewlabby wrote: 20 Aug 2020, 11:45 Hi Kimmy
I usually use this website if i get stuck and have found it good. Hope it helps

https://www.sigmaaldrich.com/chemistry/ ... lator.html
thank you
User avatar
kimmy
Posts: 418
Joined: 01 Jun 2006, 10:00
Job Title: School Lab Assistant
School: Quirindi High School
Suburb: Quirindi
State/Location: NSW

Re: Best M.W. information

Post by kimmy »

bigmack wrote: 20 Aug 2020, 11:38 Anhydrous versions have different MW.
That is why it is best to use the MW on the bottle .That way you know it matches what you have .Some recipe books don't state which type .

tin chloride.jpg
yes i think i will just go off my actual jars, thought there might have been a easier way.
Funny how it is hard to make our lives easy.
User avatar
Labbie
Posts: 3234
Joined: 28 Nov 2006, 10:00
Job Title: Retired
Suburb: At Home
State/Location: NSW

Re: Best M.W. information

Post by Labbie »

Great information above, well done folks, hats off to you all.
Regards Labbie

Lab Manager/Lab Tech, mind reading etc etc
Now retired :wub:
User avatar
J
Posts: 714
Joined: 13 Jun 2006, 10:00
Job Title: Lab Assistant
School: DHS
State/Location: NSW

Re: Best M.W. information

Post by J »

Merilyn1 wrote: 20 Aug 2020, 11:01 For molecular weight, check the individual container which will have it somewhere on the label, or, you can work it out from the formula, which will also be on the label. That would be the most reliable source.
Yes this is what I usually do.
mtg
Posts: 510
Joined: 15 Aug 2011, 10:48
Job Title: Lab Tech
School: NDSC
Suburb: west gippsland
State/Location: VIC

Re: Best M.W. information

Post by mtg »

I usually go off the container label, but I did download "Preparation of Solutions The Easy Reference" by S Rowley off chemtalk a while back. I use it to train new labbies or teachers. I also use The Laboratory but it has quite a few errors in it, if you can source "A Handbook of Laboratory Solutions. M.H.Gabb and W.E.Latchem", it is an excellent reference especially for stains and indicators.
Post Reply