Sciencemadness Discussion Board - Help me please !!!!!!! I need answer today :)

Help me please !!!!!!! I need answer today :)

Jog - 21-11-2005 at 05:13

Please help me with these two reactions...
Al + CuCl2 + H2O => ???
AL + Na2CO3 + H2O => ???

please help me ! ? ! ? !

Darkblade48 - 21-11-2005 at 05:24

It would be nice to show that you actually tried to do your homework first, before just asking people how to do something.

Most people will not look too kindly on people that just want answers, without willing to learn.

A hint for the first question: Consult a table of electronegativities and see what will happen to the more electronegative metal.

Jog - 21-11-2005 at 05:33

well, I searched in the google, but I didn't find anything, and I don't have any books with me today

but actually i'm not english so i have no idea what this thing (Consult a table of electronegativities and see what will happen to the more electronegative metal) means...

i would be very thankfull if you could help me and i'm a little bit short in time

Ashendale - 21-11-2005 at 05:41

I'm not sure, but I think it goes like this

2Al + 3CuCl2 => 2AlCl3 + 3Cu
More active metal replaces less active metal in a solution. I don't think water is needed in the equation (spelling?)

Al + Na2CO3 + H2O => Nothing happens. You just get a solution of Na2CO3 with pieces of aluminium in it...At least this is what I got when I tried it 2 minutes ago.

Should be like this... :/

[Edited on 21-11-2005 by Ashendale]

12AX7 - 21-11-2005 at 09:04

Quote:

Originally posted by Ashendale
I'm not sure, but I think it goes like this

2Al + 3CuCl2 => 2AlCl3 + 3Cu
More active metal replaces less active metal in a solution. I don't think water is needed in the equation (spelling?)

You can do it aqueous or anhydrous. The aqueous solution is vigorous, resulting in the water boiling usually, while anhydrous is a Goldschmidt type reaction, using chlorine instead of oxygen. It burns quickly, like flash powder.

Quote:

Al + Na2CO3 + H2O => Nothing happens. You just get a solution of Na2CO3 with pieces of aluminium in it...At least this is what I got when I tried it 2 minutes ago.

If the aluminum oxide layer is removed (mercury amalgam could be used), the aluminum will reduce the H2O, leaving Na2CO3 in solution and Al(OH)3 in suspension. It should react slowly, since Na2CO3 is basic and will dissolve a small amount of aluminum (not much, since CO3-- is stronger than AlO2-, correct?).

At high temperatures, the aluminum will reduce carbonate to carbide, releasing sodium as vapor at this temperature. This would be written: 3Na2CO3(l) + 10Al(l) = Al4C3(s) + 3Al2O3(l) + 6Na(g).
( (l) is liquid, (s) solid, (g) gas. Na2CO3 and/or Al may be gas at the required temperature, and I'm not sure if Al4C3 will decompose to Al(g) + C(s).)
This reaction is probably not self-sustaining. However, the analogous reaction using sulfate or nitrate instead of carbonate, proceeds quickly.

Tim

Ashendale - 21-11-2005 at 09:24

Aluminium will reduce water? Weird, never heard of it.
I've only heard that Al2(CO3)3 + H2O will result Al(OH)3 ...
Then again, I'm still a rookie and got tons to learn

woelen - 21-11-2005 at 10:05

Quote:

Originally posted by Jog
Please help me with these two reactions...
Al + CuCl2 + H2O => ???
AL + Na2CO3 + H2O => ???

please help me ! ? ! ? !

Just to make things more confusing. The reaction of CuCl2 with Al in water is VERY complex. A lot of hydrogen is produced, a small amount of copper is produced and a LOT of heat is produced.

Strangely, the reaction does not occur with CuSO4, dissolved in water. The combination of chloride ions and copper ions really is essential. So, if this was asked as a meant-to-be-simple exercise, then the person who made the exercise has chosen a very bad example.

CuSO4 + Al + water --> no reaction
CuCl2 + Al + water --> very violent reaction

CuSO4 + NaCl + Al + water --> very violent reaction

@Jog: think over this answer and go to your teacher with this. Probably he will be very surprised. Just ask him to try the reactions!

Jog - 21-11-2005 at 10:47

well this exercize was supposed to be hard because the teacher said that if anybody can do it, she'll put him 10, so i suppose it should be hard, but i need that mark

so can anybody help ? or do you think I should explain that version you guys told me to the teacher ?

[Edited on 21-11-2005 by Jog]

[Edited on 21-11-2005 by Jog]

neutrino - 21-11-2005 at 14:26

Think about the difficulty of your course and whether you would be receiving problems with the kind of explanations we are giving you. It might be that the teacher is dumb, or maybe (s)he really is trying to give you incredibly difficult problems.

What else can you tell us about the conditions of that last one? State, temperature, catalysts, and so forth?

vulture - 22-11-2005 at 12:10

Quote:

Na2CO3 solution will eat aluminium exactly because it is basic. Try mixing hot Na2CO3 solution and aluminium foil - plethora of H2.

kclo4 - 29-11-2005 at 18:29

"Just to make things more confusing. The reaction of CuCl2 with Al in water is VERY complex. A lot of hydrogen is produced, a small amount of copper is produced and a LOT of heat is produced."

you mean Hydrogen chloride right sense most aluminum compounds hydrolyze in water to make the acid especially AlCl3, but even sulfates, nitrates and others will too

so the reaction would be

2Al + 3CuCl2 + 6H2O = 3Cu + 2Al(OH)3 + 6HCl

just trying to help, n/e or anything

neutrino - 29-11-2005 at 19:06

That would happen to some extent, but mostly the equilibrium would be driven toward Al(H2O)63+ and Cl-. Removing HCl be heating would shift it to the right, though.

praseodym - 30-11-2005 at 00:27

So what is that Al complex ion called?

sparkgap - 30-11-2005 at 01:10

hexaaquoaluminum(III) would be the proper name for *THAT* complex ion.

sparky (~_~)

woelen - 30-11-2005 at 01:17

Quote:

Originally posted by kclo4
"Just to make things more confusing. The reaction of CuCl2 with Al in water is VERY complex. A lot of hydrogen is produced, a small amount of copper is produced and a LOT of heat is produced."

you mean Hydrogen chloride right sense most aluminum compounds hydrolyze in water to make the acid especially AlCl3, but even sulfates, nitrates and others will too

so the reaction would be

2Al + 3CuCl2 + 6H2O = 3Cu + 2Al(OH)3 + 6HCl

just trying to help, n/e or anything

What you state does not explain why both copper (II) and chloride are needed for the reaction.

If you replace CuCl2 by Cu(NO3)2, then no reaction occurs. The copper nitrate dissolves and the Al is sitting there, not reacting at all. The same is true for copper sulfate.

If you take Al and add that to 10% HCl, then also no reaction occurs at once. Only after quite some time the metal dissolves. If a pinch of CuSO4 is added to 10% HCl and then you add aluminium metal, then you get a violent reaction, immediately.

With CuCl2 (and also with CuSO4 + NaCl), the reaction between Al-foil and the solution is immediate and violent.

Just try it yourself to appreciate the differences. Really, there is more to be said on this than the simple hydrolysis theory.