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Chemistry Forums for Students => Inorganic Chemistry Forum => Topic started by: zhang2200 on January 24, 2015, 05:14:45 PM

Title: Not understanding molar ratios in this paper on iron oxide synthesis?
Post by: zhang2200 on January 24, 2015, 05:14:45 PM

I'm trying to synthesize a co-precipitate of silicate-iron oxide, and although I'm new at inorganic chemistry something like this shouldn't be throwing me off. Any help you could give is very much appreciated. From one paper:

Suspensions of ferrihydrite (0.1 g/100 ml) were precipitated from ferric nitrate solution (0.1 M) using 1 M KOH. The silicate was coprecipitated
with Fe³⁺. The initial concentration of silicate ranged from 10^-5 to 10^-3 M (i.e., Si:Fe = 0.001 to 0.1).

So, we know that ferric nitrate is at 0.1 M. The silicate, on the other hand is at 10^-3 or 0.001 M at the highest concentration. Wouldn't this be a ratio of 0.01 rather than 0.1 as they said? I keep running into this type of thing on all the papers I look at. I must be missing something and it's really frustrating me.

Title: Re: Not understanding molar ratios in this paper on iron oxide synthesis?
Post by: Hunter2 on January 25, 2015, 03:48:39 AM

One calculation error I see is:

Quote

Suspensions of ferrihydrite (0.1 g/100 ml) were precipitated from ferric nitrate solution (0.1 M) .

You can make from 0.1 M Ferricnitate max 0.05 M Ferrichydrite. This would give 0,85 g in 100 ml roughly.