Reef Chemistry Question of the Day # 176 Colors of chemicals

[Randy Holmes-Farley]

Reef Chemistry Question of the Day # 176

Which of the following will not be colored when pure?
(in other words, they will be white powders)

A. Iron (ferrous) sulfate
B. Copper (cupric) chloride
C. Zinc chloride
D. Potassium phosphate
E. Sodium bromide

Pick all that you think apply.

Good luck!





































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[Justiful]

C. ZnCl2

Edit:Oh ... all that apply... This will take a minute I gotta think that one I just knew.

Without looking them all up on google I am going to say potassium phosphate.
D. Kh2Po4 ...

I am pretty sure A is green, E maybe yellow. I have no clue about B... but copper makes me want to say orange.

Edit: looked it up. I wasn't completely wrong. I feel I could make a strong case for a 70% on a quiz with a grad student, or substitute teacher If the question was name all the colors. One of them is a trick.

 

[aaron23]

Too difficult of a Q lol waiting on sidelines

 

[zemuss]

C, D and E

 

[redfishbluefish]

Without looking up, I'm going to guess the only colored one is A, Iron sulfate. The rest are white. The only reason I say A is colored, and if I were to guess, an orange/brown color, is that I buy copper sulfate for my pool, and it's a pretty blue color.

 

[Bunnee911]

C,D,E. Maybe A

 

[Cory]

Zinc chloride

 

[JimWelsh]

I know that E is white, and that A and B are colored. Since the vast majority of simple salts are white, I'm going to guess that C and D are also white. So, C, D, and E.

 

[beaslbob]

I thought copper was blue

 

[Randy Holmes-Farley]

And the answer is...
C. Zinc chloride
D. Potassium phosphate
E. Sodium bromide

None of those are colored.

Hydrated ferrous sulfate is typically a light blue/green, and the anhydrous version is much lighter but usualyl still shows a bit of the same color:
http://pimg.tradeindia.com/00953448/b/1/Ferrous-Sulphate-Crystals.jpg

and cupric chloride is typically a similar color when present as the hydrate:
http://3.imimg.com/data3/BY/ML/MY-1134659/cupric-chloride-dihydrate-250x250.jpg

and sometimes brown when anhydrous:
http://anmol.org/cupricchlorideanhydrous.jpg

Happy Reefing!