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# Simple question on ionic equations... watch

1. Hi, i'm trying to revise some basics, as i always seem to get ionic equations wrong, and i'm confused on two questions i've done... (don't really know how people do subscript numbers, so Ov3 is ozone)

one question is on hydrated sodium sulfate, i put:

2Na+ (aq) + SOv4- (aq) + 20H+ (aq) + 10O2- (aq) ---> Nav2SOv4.10Hv2O (s)

2Na+ (aq) + SOv4- (aq) + 10Hv20 (l) ---> Nav2SOv4.10Hv2O (s)

without having the water molecules split into ions, i thought it was because water was the solvent but a later question was 'write an ionic equation for the reaction between potassium nitrate solution and water.' I put:

K+ (aq) + OH- (aq) + HNOv3 (l) ---> KNOv3 (aq) + Hv2O (l)

thinking that because the nitric acid was the solvent... but the answer was:

H+ (aq) + OH- (aq) ---> Hv2O(l)

which i don't understand at all, cause it treats the potassium and nitrate ions as spectator ions which they aren't cause they react too??

I think i'm just completely confused and making things up.. can anyone help?
2. (Original post by loganbell45)
Hi, i'm trying to revise some basics, as i always seem to get ionic equations wrong, and i'm confused on two questions i've done... (don't really know how people do subscript numbers, so Ov3 is ozone)

one question is on hydrated sodium sulfate, i put:

2Na+ (aq) + SOv4- (aq) + 20H+ (aq) + 10O2- (aq) ---> Nav2SOv4.10Hv2O (s)

2Na+ (aq) + SOv4- (aq) + 10Hv20 (l) ---> Nav2SOv4.10Hv2O (s)

without having the water molecules split into ions, i thought it was because water was the solvent but a later question was 'write an ionic equation for the reaction between potassium nitrate solution and water.' I put:

K+ (aq) + OH- (aq) + HNOv3 (l) ---> KNOv3 (aq) + Hv2O (l)

thinking that because the nitric acid was the solvent... but the answer was:

H+ (aq) + OH- (aq) ---> Hv2O(l)

which i don't understand at all, cause it treats the potassium and nitrate ions as spectator ions which they aren't cause they react too??

I think i'm just completely confused and making things up.. can anyone help?
If you check the balancing on the first equation you can see that you have 20 oxygen atoms on the LHS bu 10 on the RHS so its out, and then you can look at alternative manners

just remember in solutoin you always have a ready supply of OH-, H+ and H20, I generally wouldn't include O2

also on the second point they are spectator ions as their oxidation number doesnt change
3. ohhh i get the point on oxidation numbers... thank you! but on the first equation i have 10 O atoms... i still don't understand why the answer insists that the Hv2O doesn't get split into ions when doing an ionic equation - sorry my crap made up method of writing equations probably made it look too confusing :L
4. (Original post by loganbell45)
ohhh i get the point on oxidation numbers... thank you! but on the first equation i have 10 O atoms... i still don't understand why the answer insists that the Hv2O doesn't get split into ions when doing an ionic equation - sorry my crap made up method of writing equations probably made it look too confusing :L
Don't apologies I hateee ionic equations :P and you can split it up if you wish, but you can't split it up into 02, it only splits into H+ and OH-

and when you've split it and you see for instance 10 OH- + 10H+, i think you can assume that they are acting as one water molecule?
5. The posting guide tells you how to do subscripts

For the first question on hydration you have an ionic salt in water so you just need the ions + water ---> hydrate spliting up the water into ions doesn't make much sense as that's not how the vast majority of water exists.

The second question you haven't split up into ions properly:

K+(aq) + OH-(aq) + H+(aq) + NO-3(aq) ---> K+(aq) + NO-3(aq) + H2O(l)

Now cancel out the spectator ions
6. oh! :L thanks that makes way more sense now

i didn't know water split like that :L oooohh stupid error... yay, now everything clicks
7. water doesn't form ions as it is a mainly covalent molecule. it will only dissociate if an acid or base is used.

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