[onefear]

ah so the Mg+2 swaps with Cu(II)SO-2 to make Mg+2SO-2 + Cu?

btw i check the test tube it smells like the iodine and sulphur have joined and the metals have sunk to the bottom

AAAAAAAAa so the Mg never reacts with oxygen.
and the potassium reacts with the copper
so then i get potassium oxide and the copper is separate ??

[agrobert]

Well Arkcon was doing a good job but you seemed to miss the big picture.  This experiment deals with several things, the reactivity of metals, ionic dissociation, solubility and reactivity.  And sulfate is SO₄^-2.  Magnesium ribbon is Mg₀ not Mg²⁺.  Please show all your steps sequentially.

Can you write a single replacement reaction?

Also don't smell things unless you know what is going on.

This may help

http://professormeyer.com/images/solubility%20chart.jpg

[Arkcon]

Also don't smell things unless you know what is going on.

Everything agrobert: says is very important, but I did want to re-iterate this one point.  You high school chemistry book will tell you the proper way to smell chemical reactions, by wafting fumes towards your nose  without inhaling.  Oh, and it explains the other stuff we've mentioned.

Can you write the magnesium and copper sulfate reaction now?

[MrOHBrown]

To the OP...

Please take your time to explain yourself and get your explanations right. Help will come your way if you patiently and thoroughly explain what's going on.

Please stop writing SO for sulphate... Seriously. It's not how it is written and nobody will understand what you mean.

The initial reaction is a simple reduction-oxidation reaction, Mg is oxidising into Mg2+ and Cu2+ is reducing to Cu.

The reaction for the following would be: Cu²⁺_(aq) + Mg_(s) --> Mg²⁺_(aq) + Cu_(s)

As for the precipitate? Could it be the insoluble Copper (I) Iodide? It's not green but may appear so in the remaining Cu solution.

[onefear]

i know how to smell things properly oh and thanks mrOHBrown makes sense now (not all of it yet but gettin there.)
just to let you know our schools so poor we dont have chemistry books just get lectured and write note and that part we havent been taught yet.. i suppose the money goes towards the chemicals not the books i should be glad of that lol