[Jonnyb504]

So we did 3 unkowns and did great on them but now we have a bunch of questions to awnser on the chemistry envolved and a few of them have me puzzled. Any help would be appreciated even if its just pointing me in the right direction.

1. What is the role in dichloromethane in the anaylsis of iodide and bromide? Why is it neccessary to extract iodine completely before doing analysis for bromide?
2.Objects exposed ti Katrina's flood waters had a hard mineral coating. Vinegar usually was able to dissolve it. What is an analaogous behavior found in the anion anaylses and what anion could have been invovled in the coating?
3.Some stone tile was claimed to be marble, form of calcium carbonate,. You think it may be ceramic, how can you chemical tell the difference? (Does this have to do anything with adding Sulfuric acid to determine whether a it forms a gas?)

Thanks I am really stuck on these for some reason.

[hmx9123]

So ... what exactly are you doing in your experiments (it helps to know what's going on), and what have you attempted already?  In order to get help here, you need to show any work that you've done so far.

[AWK]

1. What is the role in dichloromethane in the anaylsis of iodide and bromide? Why is it neccessary to extract iodine completely before doing analysis for bromide?

Iodine in dichloromethane or chloroform or carbon tetrachloride shows a specific intense violet color.
Bromine (light brown-yellow) is masked by this color

[Jonnyb504]

We basically did a bunch of anion analysis test some of which where Bromide Iodide Carbonate ect. all of which I am assuming pertain to these questions as the other questions did.

[Jonnyb504]

Ok I've gotten 1 and 3 I am pretty sure. I still am completely lost with 2...anyone have any clue or ideas that might be a possibilty?

2.Objects exposed ti Katrina's flood waters had a hard mineral coating. Vinegar usually was able to dissolve it. What is an analaogous behavior found in the anion anaylses and what anion could have been invovled in the coating?

[LQ43]

2.Objects exposed ti Katrina's flood waters had a hard mineral coating. Vinegar usually was able to dissolve it. What is an analaogous behavior found in the anion anaylses and what anion could have been invovled in the coating?
3.Some stone tile was claimed to be marble, form of calcium carbonate,. You think it may be ceramic, how can you chemical tell the difference? (Does this have to do anything with adding Sulfuric acid to determine whether a it forms a gas?)

#2 and #3 are related. Vinegar is a dilute solution of acetic acid. Vinegar is used to remove the hard scale that builds up in kettles that boil water. So what anion would be involved?

[Jonnyb504]

Carbonate?

[LQ43]

yes, carbonate is a reasonable answer but any other anion that would react with an acid to give an aqueous solution would work. Oxides would also be dissolved by acids.

[Alpha-Omega]

Question 2.  Carbonate
Question 3:  There is a huge difference between ceramic and limestone....and limestone is carbonate and a traditional analytical test in geochemistry is the application of sulfuric acid....this is done with microscopy and YES if it is limestone it will buble up.....and thermal testing....use a 650 to 800 degree C oven....the carbonate will burn up....the ceramic will not.  usually cermaics have refractory materials in them that will withstand high temperatures....

I am an Inorganic Chemist...let me think on DCM issue....but I think I know....let me do some checking....