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rphrph8 rphrph8
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9 years ago
We got an unknown acid. mass of unknown acid is 0.208g. Volume of standardized base used is 7.08ml which I got from final buret reading - initial. The given base is 5N NaOH.

I need help figuring out:
1. the molarity of standardized base solution?
I think it is 5M because it's 1:1 ratio of NaOH to OH- ions.  So 5N is equal to 5M. Not sure if correct.  

2. Mole of base consumed? Once I get Molarity then I can multiply molarity with volume in liters. . Correct?

3. Mole of acid?
4. Molecular weight of unknown acid?

Been struggling and can't figure it out. Any help would be greatly appreciated.  

Thanks in advanced.  
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9 years ago Edited: 9 years ago, ortho2122
1) and 2) are correct; normality is based on the number of equivalents - in this case acid or base - per formula weight. You can't say much about 3) or 4) without more information. All you can really determine is the number of acid equivalents there were in .208 g of material. You need to know at least a composition of the unknown to calculate an estimate of the MW.
Post Merge: 9 years ago

I take that back a little...if you can assume that the acid was mono-protic (or di-protic, etc.) and you know the total volume of everything (unknown + water (if used to dissolve the unknown) + NaOH solution added), then you can estimate the molecular weight.
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