[FeRocks]

How many mL's of concentrated hydrochloric acid, 38% (wt/wt), specific gravity 1.19 are required to prepare 1 L of a 0.100 M solution?  Assume density and specific gravity are equal within three sig figs.  I have no idea how to incorporate the specific gravity part. help please! thanks.

[Alpha-Omega]

Same thing solved here in the forum:  http://www.chemicalforums.com/index.php?topic=21647.msg82701#msg82701

It goes like this:
Molarity:  Moles/L

HCl = 38.0%
Density = 1.19 g/cm^3  = 1.19 g/mL
GFW HCl = 36.45 g/mol

To find the molarity M use this: M = mol/L…those are you units

Use the density to calculate the weight of 1 liter of solution-
1000 mL x 1.19 g/mL = 1190 grams
Use the percent to calculate the mass of HCl in 1190 g (1.000 liters)-
1190 x  38.0% =  1190 x 0.38 = 452.2 g HCl


Now you know the weight of HCl per liter.

Convert the weight of HCl to moles of HCl-
452.2 g / 36.45 g/mol = 12.406 moles  or 12.41 moles of HCl in 1.000 liter
Molarity = 12.41 M

Now for the rest  concentrated M = 12.41 and diluted desired is 0.100M  so do the rest:

Use M1V1 = M2V2

Or as previously stated:  Mconc  x Vconc = Mdil x Vdil

Rearranging gives you Vconc = (Mdil x Vdil)/Mconc

[Borek]

http://www.chembuddy.com/?left=concentration&right=toc

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