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Offline arul

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Re: simple but confusing
« Reply #15 on: November 11, 2013, 02:01:05 AM »
Ok so if your equation is correct

2HNO3 + BaCO3 :rarrow: Ba(NO3)2 +CO2 + H2O

Then this is not an equimolar reaction, you have two mols of nitric acid and only one mole of Barium carbonate.

So I am a bit confused by what you are asking, I apologise if I am being a bit slow on the uptake.


My understanding for "equimolar formula" is equal mole calculation for  two compounds ( A & B ). If two  compounds are solid I know the method but for  solid(A) and liquid (B) combination Is there any "formula ".

The above mentioned equation is not an example of equimolar ratio (1:1). It is an example of (2:1) ratio. 2 moles of nitric acid and 1 mole of barium carbonate.

           I thought if i can find out how to calculate one mole of nitric acid I can find out 2 moles by myself.



Let us assume that both are solids, replace any volumes in ml to grams. How would you solve this problem?

For two solid components . for Example
Compound "A" --> glycine ( M.w = 75.07 g/mol )

 If i dissolve 75.07 grams in 1000 ml i get one mole.
so in 100 ml solution if I dissolve 7.5 grams I will get 1 mole.

similarly for compound "B"

Barium nitrate --> ( M.W = 261.337 g/mol)

If i dissolve 261.337 grams in 1000 ml I get one mole.
so in 100 ml solution if I dissolve 26.13 grams I will get 1 mole.

So in a 100 ml solution If I take 7.5 g grams of glycine and 26.1 grams of barium nitrate this is called equimolar ratio ( 1:1) . This is what I am following for solid + solid combination. Correct me If I am wrong?

Offline Borek

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Re: simple but confusing
« Reply #16 on: November 11, 2013, 04:00:35 AM »
If i dissolve 75.07 grams in 1000 ml i get one mole.

What is the molar concentration then?

Quote
so in 100 ml solution if I dissolve 7.5 grams I will get 1 mole.

No, you don't. You get 0.1 mole.

Quote
If i dissolve 261.337 grams in 1000 ml I get one mole.

What is the molar concentration then?

Quote
so in 100 ml solution if I dissolve 26.13 grams I will get 1 mole.[/quote[

No, you don't. You get 0.1 mole.

Still, 0.1:0.1 means equimolar.

Do you see now the link between concentrations and moles?
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Offline arul

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Re: simple but confusing
« Reply #17 on: November 11, 2013, 05:57:40 AM »
If i dissolve 75.07 grams in 1000 ml i get one mole.

What is the molar concentration then?

Molar concentration is 1 M

Quote
so in 100 ml solution if I dissolve 7.5 grams I will get 1 mole.

No, you don't. You get 0.1 mole.

Quote
If i dissolve 261.337 grams in 1000 ml I get one mole.

What is the molar concentration then?

Molar concentration is 1 M

Quote
so in 100 ml solution if I dissolve 26.13 grams I will get 1 mole.[/quote[

No, you don't. You get 0.1 mole.

Still, 0.1:0.1 means equimolar.   

Do you see now the link between concentrations and moles?

My apology I miscalculated 1 mol instead of 0.1 mol for 100 ml solution. thanks for correcting me.

Yes Now I see the relation between moles and concentration.  If I want 2M solution of barium nitrate Instead of 26.13 grams in 100 ml if I dissolve 52.26 grams in 100 ml i will get. Till here I am clear with how to take equimolar ratio of two solid substances and to make 1M, 2M concentrations.

 But how to take equimolar  ration of any  Liquid+ liquid compounds as well as solid + liquid compounds.

Offline Borek

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Re: simple but confusing
« Reply #18 on: November 11, 2013, 06:53:33 AM »
Equimolar means identical number of moles. Doesn't matter if substances come in the form of a solution (in which case number of moles can be easily calculated by solving molar concentration definition [itex]C=\frac n V[/itex] for n), solid or gas.
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