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HELP !! how can i identefy an unknown metal (I have less than 24h)? Answered

For chemestry I have to Identify an unknown metal by causing a GAS REACTION, it can be any metal !
- I can't incinerate the metal
- I can't mix the metal with water
- I can't measure the volume of the metal

There must be a gas reaction !!
I probably have to use some kind of acid and measure the mass before and after the reaction i think.

PLZ HELP ME !! i have to know it in less then 24 houres ! it is very important for my grades.

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lemonie (author)2011-11-06


What is the exact, verbatim question or description of the task?

L

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anres321 (author)lemonie2011-11-06

As you have probably noticed English is not my vernacular but translated into english it woul be something like this: "you have some peaces of an unknown metal. use a gas reaction to identify the metal given metal."

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lemonie (author)anres3212011-11-06


Gas-reaction?
I don't get it, but to be tenuous, as flame is a "gas-reaction"
You dissolve the metals in concentrated nitric acid, prepare a sample and put it through a Flame Atomic Absorption Spectrometer.

L

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Kiteman (author)lemonie2011-11-06

Or react it with *any* acid, evaporate the liquid to leave a solid salt, stick the solid salt to a piece of platinum wire and then poke it in a bunsen flame to see what colour the flame goes.

Relevant earch results.

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anres321 (author)Kiteman2011-11-06

yeah,, the only problem is that we dont have platinum wire to our disposal.

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Kiteman (author)anres3212011-11-06

Then dissolve the salts in water (saturated solution), and soak wooden splints in the the solutions overnight.

Wave the splints in the flames long enough to see the colours, but not so long as to char the wood, which would spoil the colours you see. Check the wikipedia link for more details.

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steveastrouk (author)anres3212011-11-06

You don't need one. you can put a sample in a piece of graphite/on the end of a pencil.

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lemonie (author)Kiteman2011-11-06


Nah, crystallise it and get a big expensive x-ray-crystallogram..

L

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frollard (author)2011-11-06

"I can't dissolve the metal" -- "I probably have to use some kind of acid"

....that would defeat the purpose of that rule.

You need to get the metal in the presence of various gasses and see which ones cause reactions; from reactivity charts you'll be able to tell what metal it is by eliminating the ones that don't react. I'll leave it to you to FIND these charts and build a procedure that best eliminates the most metals.

If it's just 'in air' -- many alkali metals will tarnish in the presence of air (oxygen), and get different colours of tarnish. By knowing the speed of the reaction/colour of the oxide you know what the metal is.

Given that it's chemistry class they probably won't give you anything more reactive than sodium or potassium (which light on fire/sometimes explode in water).

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anres321 (author)frollard2011-11-06

thanks to reply !! with "dissolve" i meant mixing it with water. Not getting effected by the acid. I'm sorry for the misunderstanding, My native language is Dutch, I probably didn't use the right word. The problem with your solution is that it could be ANY metal. if we have to determinate we will have to use a lot of different acids and this would take to long. I think it we have to use some an acid and weigh the mass after the reaction and see how much of the metal is still left. But I don't seem to find a proper way to determinate the metal. but thank you very much to reply !

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frollard (author)anres3212011-11-06

Right; but unless there's a translation issue, you'll have a hard time finding acid 'gas'.

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anres321 (author)frollard2011-11-06

No but i thought if an acid reacts with gas it creates gas ?

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frollard (author)anres3212011-11-06

a 'gas' reaction would be 'metal in air tarnishes'.

It's true you can get acidic gasses, but I'm sure that's not what your chemistry assignment is.

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anres321 (author)frollard2011-11-06

But say I use this: METAL + HCL -> METAL,CL + H2(gas) not ?

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