[chemicalX]

Hi all

I need some help please:

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

Thank You

[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.

[chemicalX]

(Original post by shengoc)
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.

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

cheers

[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.

[chemicalX]

(Original post by shengoc)
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.

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

Im still confused?

thanks

[chemicalX]

(Original post by shengoc)
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.

Please help... im really confusedo

also im giving you + rep.

Cheers

[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)?

[chemicalX]

(Original post by shengoc)
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)?

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

[shengoc]

(Original post by chemicalX)
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

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.

[thegodofgod]

(Original post by chemicalX)
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

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?

[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?

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.

FANTASTIC!

I got it!

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

Is that correct?

Cheers

[chemicalX]

(Original post by thegodofgod)
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?

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

Cheers

[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!

[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

Cheers

[DH3498]

(Original post by thegodofgod)
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?

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 Thanks for all responses

[chemicalX]

(Original post by DH3498)
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 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.

[DH3498]

(Original post by chemicalX)
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.

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!

[chemicalX]

(Original post by DH3498)
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!

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

[BhaJack]

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

[illusionz]

(Original post by BhaJack)
Take it you done the ocr isa what did you get for the final electrode potential one with the 3 mistakes?

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