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Thermal Decomposition of NH4VO3 ?? Help!!!!!

chemicalX

Hi all

I need some help please:

what is the Thermal Decomposition of Ammonium Vanadate (NH4VO3)?

Thank You

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Reply 1

shengoc

Original post by chemicalX

Hi all

I need some help please:

what is the Thermal Decomposition of Ammonium Vanadate (NH4VO3)?

Thank You

stable end products are usually the oxides of the metal. ammonium salts usually decompose to form a pungent gas. if your equation requires balancing, water or steam could be given off - depending on your thermal conditions.

Reply 2

chemicalX

Original post by shengoc

ok, im not quite sure what you mean, but im i right in thinking that the decomposition products will be -> NH4 and VO3?

cheers

Reply 3

shengoc

Original post by chemicalX

ok, im not quite sure what you mean, but im i right in thinking that the decomposition products will be -> NH4 and VO3?

cheers

do you know what NH4 is? do you know what is its shape? and do you know oxidation state of V in VO3? check in periodic table to see if this is possible - work this out from the electronic configuration of the V atom.

Reply 4

chemicalX

Original post by shengoc

NH4 is an ammonium ion, its got a tetrahedral shape, V is in +5 oxidation state.

Im still confused?

thanks

Reply 5

chemicalX

Original post by shengoc

Please help... im really confused :o:

also im giving you + rep.

Cheers

Reply 6

shengoc

Original post by chemicalX

NH4 is an ammonium ion, its got a tetrahedral shape, V is in +5 oxidation state.

Im still confused?

thanks

ok, you do know your stuff. thermal decomposition doesn't produce naked ions - usually gases are given off. also V is +6 in VO3, which by the way doesn't exist as after the 4d and 3d electrons are removed, the sixth ionisation energy is too great to overcome.

since you know the max oxidation state of V, you should be able to work out the stable oxide of V. you know what is the V catalyst used in manufacture of sulphuric acid(the Contact process)?

Reply 7

chemicalX

Original post by shengoc

So is the oxidation state of V in nh4vo3 - +6?? i thought it was +5. Never mind that, more importantly, yes in the contact process v2o5 is used as a catalyst.

sorry i just cant work out what the products will be :frown:

Reply 8

shengoc

Original post by chemicalX

ok, im not quite sure what you mean, but im i right in thinking that the decomposition products will be -> NH4 and VO3?

quoting what you mentioned before, if they are without charge, then V in VO3(no charge) would be +6, which again, I must stress doesn't exist.

so V2O5 is a stable oxide of V. that could be one of the products, couldn't it? you should be able to work out the rest. it is just plain balancing equations. use your chemistry intuition. you do seem to me like someone who actually knows your chemistry well.

Reply 9

thegodofgod

Original post by chemicalX

Remember, the vanadate ion is negatively charged, VO₃^-.

As each oxide has a oxidation state of -2, then the vanadium must have an oxidation state of +5, which is vanadium's maximum (feasible) oxidation state.

The pungent gas shengoc was talking about is ammonia, which has the formula NH₃.

So, if the products of the thermal decomposition are: Vanadium (V) oxide, Ammonia and something else, can you work out what the last product is by writing out a balanced equation?

Reply 10

chemicalX

Original post by shengoc

FANTASTIC!

I got it!

2NH4VO3 ----> 2NH3 + V2O5 + H2O

Is that correct?

Cheers

Reply 11

chemicalX

Original post by thegodofgod

Yes thanks for your help! i figured it out thanks to you all!!!

Cheers

Reply 12

shengoc

Original post by chemicalX

Yes thanks for your help! i figured it out thanks to you all!!!

Cheers

took you a while, but you got it!

Reply 13

chemicalX

Original post by shengoc

took you a while, but you got it!

Haha thanks! i really appreciate it! i cant give you anymore + rep, it says that ive already rated you, please rate someone else??

Ill rep you more tomorrow :smile:

Cheers

Reply 14

DH3498

Original post by thegodofgod

What are the state symbols of this reaction? I was trying to work it out; would they all be (aq)? Because I heard it need higher temps, therefore would H20 be given off as a gas?

Finally, how would u show the reaction is complete?... Steam has stoppped being produced?

So for all the questions :smile:

Thanks for all responses

Reply 15

chemicalX

Original post by DH3498

Thanks for all responses

Yes you are correct. H2O would be given off as steam i.e in gaseous form.

You get the compound, in this case NH4VO3 and heat it (thermal decomposition) and gasses will be given off (NH3 and H2O) you will have to weigh the substance before heating, then weigh after heating. leep on repeating the process until you reach constant mass. This proceses where you know the reaction is complete is called - heating to constant mass.

Reply 16

DH3498

Original post by chemicalX

Ahhh, so you're repeating the experiment once you know the mass of the product (V2O5)? Then when you reach that mass, you can deduce that the reaction is complete. And then at that stage, NH3 and H20 release should stop too?

Thanks!

Reply 17

chemicalX

Original post by DH3498

Yeah sort off...

for example, the mas of nh3vo3 is 1.498g, i heat it and weigh it - 1.36g then i heat again and reweigh - 1.35 i repeat - 1.35g and therefore the mass is constant.

As you know the mass decreases as nh3 and h2o are given off and once they are no longer being released, the mass stays the same.

Cheers :smile:

Reply 18

BhaJack

Take it you done the ocr isa what did you get for the final electrode potential one with the 3 mistakes?