Sciencemadness Discussion Board

Net Ionic Equation - little help please

smaerd - 28-9-2010 at 16:17

I have some basic questions. My text book is no help. I understand the concept, at least I think I do, could someone check this one problem for me and make sure I've got the right idea.

Say the problem is this:
Write the ionic and net ionic equation for the following reaction:
Mg(NO3)2(aq) + 2NaOH(aq) ->

Here's what I have:

For the standard balanced equation.
Mg(NO3)2(aq) + 2NaOH(aq) -> Mg(OH)2(aq) + 2Na(NO3)(s)

Now for ionic equation. Here's where I am getting a little hung up. So the subscripts of the polyatomic ions such as Nitrates, say I have 2 Nitrates on the Magnesium Nitrate. Do I move the subscript to become a coefficient or leave it as a subscript? Did I do this right?
Mg(+2) + 2(NO3)(-1) + 2Na(+1) + 2(OH)(-1) -> 2Na(+1) + 2(NO3)(-1) + Mg(OH)2(s)

Then here is what I have for the net ionic equation. So for the net ionic equation I remove all of the spectator ions pertaining to the reaction(Ions not being used directly for the reaction). In this case a metathesis precipitate reaction.

So even though the Nitrate, is bouncing from the magnesium and being replaced by a Hydroxide it is considered a spectator ion right?
Mg(+2) + 2(OH)(-1) -> Mg(OH)2


Thanks for any help. I hope I didn't type to much I was just trying to be clear as to where I am stuck.

[Edited on 29-9-2010 by smaerd]

crazyboy - 28-9-2010 at 16:33

You need to add a coefficient of 2 to the nitrate anion because as it is now the ionic equation is not balanced.

smaerd - 28-9-2010 at 16:39

Oh right I just forgot to type that I have it down on paper, thank you:D. I fixed that now. Does it look okay otherwise?

[Edited on 29-9-2010 by smaerd]