Yr 12. Determination of Keq by Colorimetry

A general discussion and Q & A forum.
Post Reply
User avatar
macca
Posts: 992
Joined: 10 Dec 2008, 08:38
Job Title: Mind Reader
State/Location: NSW

Yr 12. Determination of Keq by Colorimetry

Post by macca »

Hi Brains trust,

Person Chemistry 12 prac.5.4

Is anyone having a win doing this practical? This is the second year we are having no luck with results.

Thanks in advance
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: Yr 12. Determination of Keq by Colorimetry

Post by kimmy »

iv just been given this prac to get ready and trying to work out the chemicals at the moment.
User avatar
macca
Posts: 992
Joined: 10 Dec 2008, 08:38
Job Title: Mind Reader
State/Location: NSW

Re: Yr 12. Determination of Keq by Colorimetry

Post by macca »

Hi Kimmy

Yep a real nightmare. This year, different teacher has tried a variation and is getting some results although not the higher readings that were sort.

Using 0.1M HNO3
0.5M KSCN
0.0001M Fe(NO3)3

0.0025M KSCN
0.0025M Fe(NO3)3
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: Yr 12. Determination of Keq by Colorimetry

Post by kimmy »

Thank you, ill let you know how we get on next week. :banghead2:
bigmack
Posts: 816
Joined: 15 Dec 2015, 10:49
Job Title: Lab Technician
School: FCAC
State/Location: QLD

Re: Yr 12. Determination of Keq by Colorimetry

Post by bigmack »

We just did it .Chem teacher used an old book they used to do it 20 years ago .

0.2M Fe(NO)3
0.002M KSCN

He said it worked a teat . I wonder if your books have typos in them and the Molarities are back to front
Merilyn1
Posts: 1476
Joined: 12 Mar 2013, 08:10
Job Title: Labbie
School: Wollondilly Anglican College
Suburb: Tahmoor
State/Location: NSW

Re: Yr 12. Determination of Keq by Colorimetry

Post by Merilyn1 »

My Chem teacher uses 5ml each of 0.2M Ferric Nitrate and 0.2M of KSCN. Seems happy with that.
ctzavellas
Posts: 9
Joined: 19 Feb 2008, 13:11
Job Title: Laboratory Technician
School: PLC Sydney
Suburb: Croydon
State/Location: NSW

Re: Yr 12. Determination of Keq by Colorimetry

Post by ctzavellas »

Hey bigmac,

Which textbook is your chem teacher using, as we too are getting some weird results? Could you please find out for me.
Thnks

Carlie
bigmack
Posts: 816
Joined: 15 Dec 2015, 10:49
Job Title: Lab Technician
School: FCAC
State/Location: QLD

Re: Yr 12. Determination of Keq by Colorimetry

Post by bigmack »

ctzavellas wrote: 04 Nov 2019, 11:33 Hey bigmac,

Which textbook is your chem teacher using, as we too are getting some weird results? Could you please find out for me.
Thnks

Carlie
Hi Carlie
It's an old text book called Chemical Science ,Laboratory Manual ,Carswell.
We have both the student version and the teachers version which has answers in it .


out of interest I was telling my Chem teacher that some were having issues with it . He pointed to the answers obtained in the teachers version of the book and suggested that perhaps the teachers were expecting exact number constant on each test whereas in reality there is a spread of answers that are around the constant value expected .

Here's a cropped screen shot of the pdf copy of the teachers version of the book .
Equalibrium.png
Equalibrium teachers answers.pdf
Equalibrium.pdf
You do not have the required permissions to view the files attached to this post.
User avatar
macca
Posts: 992
Joined: 10 Dec 2008, 08:38
Job Title: Mind Reader
State/Location: NSW

Re: Yr 12. Determination of Keq by Colorimetry

Post by macca »

Thanks
ctzavellas
Posts: 9
Joined: 19 Feb 2008, 13:11
Job Title: Laboratory Technician
School: PLC Sydney
Suburb: Croydon
State/Location: NSW

Re: Yr 12. Determination of Keq by Colorimetry

Post by ctzavellas »

Hey Macca,

Did you guys use both the method of matching the color by eye and colorimeter for this prac?

Carlie
ctzavellas
Posts: 9
Joined: 19 Feb 2008, 13:11
Job Title: Laboratory Technician
School: PLC Sydney
Suburb: Croydon
State/Location: NSW

Re: Yr 12. Determination of Keq by Colorimetry

Post by ctzavellas »

ctzavellas wrote: 04 Nov 2019, 14:22 Hey Macca,

Did you guys use both the method of matching the color by eye and colorimeter for this prac?

Carlie
User avatar
macca
Posts: 992
Joined: 10 Dec 2008, 08:38
Job Title: Mind Reader
State/Location: NSW

Re: Yr 12. Determination of Keq by Colorimetry

Post by macca »

Yes we did, they are going to give that old method above ago next year. Think just ended up speculating on what the results should have bwen.
Post Reply