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Chemistry Forums for Students => High School Chemistry Forum => Topic started by: scavok on September 24, 2004, 01:07:27 AM

Title: moles to mL?
Post by: scavok on September 24, 2004, 01:07:27 AM

I've been trying to figure this problem out for atleast an hour, I just don't understand how to get the volume.  There are no examples of such problems in my textbooks, only problems to get the mass, not volume.  

Here's the question verbatim:

Quote

What volume (mL) of 6.0M H2SO4 should be taken in order to prepare 50.0 mL of a solution which is 0.25M in H2SO4?

The molecular weight of H2SO4 is 98.078amu (g/mol)

I don't really even know where to start.  I guess you would need the amount of grams in .25M of H2S04, which is 24.520g.  But how the heck do you get volume?  You would need the density, wouldn't you?

Maybe if someone could just rewrite the question using different terms I would understand it.  It doesn't even seem like it's written in english to me.

Thanks for the help

Title: Re:moles to mL?
Post by: jdurg on September 24, 2004, 01:20:26 AM

(M1)(V1) = (M2)(V2).  Just solve for V1 since you have M1, M2, and V2.

Title: Re:moles to mL?
Post by: 1cesoul on September 24, 2004, 04:54:27 AM

1 ml = 1 cm³
1M= 1 mol/dm³

n(H2SO4) needed= 50/1000*0.25=0.0125mol

since conc of H2SO4 ish 6M

vol needed = 0.0125/6 dm³
                 = 2.08 ml