CNJ wrote:I know that: 5.00 grams HCl per 100 ml of solution

I also know that the equivalence point is at 18 ml.

I need to find the moles of HCl in 18 ml.

How do I do this?!

Density = mass/volume = 5/100= .05 but what do I do with density?? How do I get moles of HCL out of 18ml??

1) First use concentration to determine grams of HCl in 18 mL:

5 g/100 mL x 18 mL = 0.9 g HCl

2) Determine molecular weight to get molar mass. From periodic table, H = 1.008, Cl = 35.453, hence HCl = 36.461. This is also the molar mass in g/mol.

0.9 g x 1 mol/36.461 g = 0.02468 nol = 24.68 mmol.