Forensics C
-
- Member
- Posts: 20
- Joined: March 15th, 2016, 8:06 pm
- Division: C
- State: GA
- Has thanked: 0
- Been thanked: 0
Re: Forensics C
Does Borax react the same way as Boric Acid? Especially flame-test and solubility-wise? My coach is reluctant to buy Boric Acid because we have Borax, but I want to make sure they are the same thing. I did some research and am wondering if the sodium in Borax would cause the flame to be yellow instead of green...
- pikachu4919
- Moderator
- Posts: 716
- Joined: December 7th, 2012, 2:30 pm
- Division: Grad
- State: IN
- Pronouns: She/Her/Hers
- Has thanked: 89 times
- Been thanked: 167 times
Re: Forensics C
Sodium turns everything yellow regardless of how much of it there is. But either way, despite that both borax and boric acid have boron in them, the boron is positioned in the molecules in totally different ways in that they have completely different chemical formulas (Na2B4O7·10H2O vs H3BO4, literally a buffer vs an acid), and thus, they will not react in the same ways. As much as we all wish it wasn't, chemistry is complicated, buddy.Lumitailz wrote:Does Borax react the same way as Boric Acid? Especially flame-test and solubility-wise? My coach is reluctant to buy Boric Acid because we have Borax, but I want to make sure they are the same thing. I did some research and am wondering if the sodium in Borax would cause the flame to be yellow instead of green...
-
- Member
- Posts: 3
- Joined: May 12th, 2015, 6:28 am
- Division: Grad
- State: MI
- Has thanked: 0
- Been thanked: 0
Re: Forensics C
Sodium acetate is a fine white powder but will become a crystal when exposed to water (ex. humidity) according to my cheat sheetpikachu4919 wrote:Yeah I mean considering the national supervisor's description of sodium acetate is "very fine white powder" and the sample of sodium acetate we had at our school was medium-sized clear crystals, I'd say really don't rely on the physical appearance of the powder as a key identifier. There are plenty of other ones you can use that are far more robust.Magikarpmaster629 wrote:I don't think crystal shape works well for IDing powders, although I haven't tried much. I think they're extremely variable, and lack of consistency makes it hard to ID. I would think that at least KCl would also have a cubic structure, since it's very similar chemically to NaCl.daydreamer0023 wrote:Just wondering, is salt the only powder with a cubic crystal? Silly question, I know.
- Panda Weasley
- Member
- Posts: 133
- Joined: September 27th, 2014, 6:24 am
- Division: C
- Has thanked: 0
- Been thanked: 2 times
Re: Forensics C
I believe that PMMA has a bright blue flame with no smoke and a fruity smell.bradyr18 wrote:Does anyone have the burn test results of PMMA, I know we can't conduct burn tests in the event but the rules specify that the results can be given.
- pikachu4919
- Moderator
- Posts: 716
- Joined: December 7th, 2012, 2:30 pm
- Division: Grad
- State: IN
- Pronouns: She/Her/Hers
- Has thanked: 89 times
- Been thanked: 167 times
Re: Forensics C
Idk about you guys but when I did this event, I felt like the only burn test result that I thought was absolutely necessary to know was PVC, which is a green flame, and then the rest can be determined by density.Panda Weasley wrote:I believe that PMMA has a bright blue flame with no smoke and a fruity smell.bradyr18 wrote:Does anyone have the burn test results of PMMA, I know we can't conduct burn tests in the event but the rules specify that the results can be given.
Granted, this largely depends on the supervisors at each competition and what information they choose to provide for you, so don't take my word for it that PVC's flame is the only one you need to know.
Carmel HS (IN) '16
Purdue BioE '21? reevaluating my life choices
Nationals 2016 ~ 4th place Forensics
"It is important to draw wisdom from different places. If you take it from only one place, it becomes rigid and stale." -Uncle Iroh
About me || Rate my tests!
Opinions expressed on this site are not official; the only place for official rules changes and FAQs is soinc.org.
MY CABBAGES!
Purdue BioE '21? reevaluating my life choices
Nationals 2016 ~ 4th place Forensics
"It is important to draw wisdom from different places. If you take it from only one place, it becomes rigid and stale." -Uncle Iroh
About me || Rate my tests!
Opinions expressed on this site are not official; the only place for official rules changes and FAQs is soinc.org.
MY CABBAGES!
- sciduck
- Exalted Member
- Posts: 98
- Joined: May 7th, 2016, 4:50 pm
- Division: C
- State: MN
- Has thanked: 0
- Been thanked: 0
Re: Forensics C
I've seen questions on the burn test for PS and LDPE/HDPE too, but I would say that it definitely depends on test writers.pikachu4919 wrote:Idk about you guys but when I did this event, I felt like the only burn test result that I thought was absolutely necessary to know was PVC, which is a green flame, and then the rest can be determined by density.Panda Weasley wrote:I believe that PMMA has a bright blue flame with no smoke and a fruity smell.bradyr18 wrote:Does anyone have the burn test results of PMMA, I know we can't conduct burn tests in the event but the rules specify that the results can be given.
Granted, this largely depends on the supervisors at each competition and what information they choose to provide for you, so don't take my word for it that PVC's flame is the only one you need to know.
——————————————— SCIDUCK uses CONFUSION! ———————————————
-
- Member
- Posts: 20
- Joined: March 15th, 2016, 8:06 pm
- Division: C
- State: GA
- Has thanked: 0
- Been thanked: 0
Re: Forensics C
I never quite understood how to do density tests- Do you use a beaker and fill the whole thing up with liquid? Or can you use test tubes? Plastics have always been a part of the test I just guessed on.
- Magikarpmaster629
- Exalted Member
- Posts: 578
- Joined: October 7th, 2014, 3:03 pm
- Division: Grad
- State: MA
- Has thanked: 0
- Been thanked: 1 time
Re: Forensics C
If you're doing plastics, the event supervisor will provide solutions of different densities. Since you can bring a chart with the densities of each plastic and the densities of the solutions, you can tell which plastics will sink/float in which solutions. At the event, you take the plastic and simply place it in the liquid to see whether it floats or sinks.Lumitailz wrote:I never quite understood how to do density tests- Do you use a beaker and fill the whole thing up with liquid? Or can you use test tubes? Plastics have always been a part of the test I just guessed on.
Ladue Science Olympiad (2014ish-2017)
A wild goose flies over a pond, leaving behind a voice in the wind.
A man passes through this world, leaving behind a name.
A wild goose flies over a pond, leaving behind a voice in the wind.
A man passes through this world, leaving behind a name.
-
- Member
- Posts: 20
- Joined: March 15th, 2016, 8:06 pm
- Division: C
- State: GA
- Has thanked: 0
- Been thanked: 0
Re: Forensics C
So for example, if the supervisors provide us with a large bottle of alcohol for a row to share, we can just dunk the plastic directly into the alcohol container?Magikarpmaster629 wrote:If you're doing plastics, the event supervisor will provide solutions of different densities. Since you can bring a chart with the densities of each plastic and the densities of the solutions, you can tell which plastics will sink/float in which solutions. At the event, you take the plastic and simply place it in the liquid to see whether it floats or sinks.Lumitailz wrote:I never quite understood how to do density tests- Do you use a beaker and fill the whole thing up with liquid? Or can you use test tubes? Plastics have always been a part of the test I just guessed on.
Who is online
Users browsing this forum: No registered users and 9 guests