[beheada]

If I have some sulfuric acid that has an unknown concentration, how would I go about finding it in percentage terms? And would anyone care to explain how concentration and molarity are related? I think I'm confusing myself when the answer's really quite simple...

[Alberto_Kravina]

You could titrate it with NaOH n=0,1 mol/L.
You must have at least an approximated concentration of the acid so that you can diluite it to approx. 0,1N and titrate it with NaOH. To determine the percentage you also need the denlity of the acid, which you could measure with a picnometer or an areometer.

And would anyone care to explain how concentration and molarity are related?

Errr...I don't understand, could you explain it a bit better.

[Borek]

Unclear to me what you are trying to do. If the acid has unknown concentration the only way to find its concentration (expressed in any units) is to analyze sample (see Alberto's post).

However, second part of your question suggests that you think in terms "percentage is concentration, molarity is molarity". If so, first - molarity is the concentration as well. And to convert between both you may either use ready cheat-sheet:

http://www.chembuddy.com/?left=CASC&right=concentration-cheat-sheet

or you may read these lecture notes to learn how to do it:

http://www.chembuddy.com/?left=concentration&right=percentage-to-molarity

(note that you may have to solve final equation for percentage to be able to convert, but the general idea is described precisely enough).

[AWK]

You can also measure a density of solution and find any kind of concentration from tables (assuming you have a pure solution of sulfuric acid)

[Donaldson Tan]

What percentage are you looking for? There is more than one type of percentage. eg. percentage by mass, percentage by volume, percentage by moles, percentage dissociation.

[beheada]

I can do the titration with NaOH, then to find the density weigh the acid and divide by the volume then get the percentage that way... correct?

What I'm trying to figure out, is when I read in literature (articles, etc) a 2% sulfuric acid was added, does that mean 2% concentration and if that's the case, don't I just need to do a M1V1 to get to my desired concentration.

In my chem class, concentration was synonymous with molarity and we used the terms interchangably, but I always read about concentration in terms of percentage and molarity in terms of moles/liters (or the actual number itself).

I think I'm getting confused by the terminology that different literature uses. For example, the write-up I read concerning the oxidation of hydroquinone to quinone using vanadium pentoxide requires a very dilute sulfuric acid solution. I was attempting to find the starting concentration of my H2SO4 so that I could dilute it correctly.

Hope that clears up my position.
Thanks for the help.