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ch3m
Nov1-11, 08:31 AM
Hi guys,
I'm facing a problem.
I've read a paper where they tried to synthesise a crystal and they give the following reaction mixture molar composition:
3.0 SiO2
1.0 Al2O3
0.1 NaCl
276 H2O

What does it means?
It can't be the molar fraction since the sum of all the fraction must give 1 as result.
I guess that it should be the mol of each compound in solution, but that means that they have almost 5 L of water.... am I right?

Borek
Nov1-11, 08:58 AM
I guess that it should be the mol of each compound in solution, but that means that they have almost 5 L of water.... am I right?

That's how I would read the information.

No idea why they reported it this way, perhaps that's a convention used in such papers.

ch3m
Nov1-11, 09:46 AM
That's how I would read the information.

No idea why they reported it this way, perhaps that's a convention used in such papers.

Thanks.

So can I take such values as a ratio??

I mean: 3.0:1.0:0.1:276

So if I fix a volume of 250 ml of water which means 13.877 mol, I need to divide the mols for 276 and then multiply for the ratio.
i.e. for Al2O3 --> 13.887*(1/276) and for NaCl 13.887*(0.1/276)
Right?

Borek
Nov1-11, 10:36 AM
Looks OK.