I have a problem that involves using a few equations. This is the problem: Calcium and EDTA react in a 1:1 ratio. 2.3ml of EDTA .01M has been used to titrate 25ml of the unknown solution. So i've multiplied 2.3 by .01 yielding a result of .00023 M. I'm not sure where to go from here, do I divide 25 by 2.3 and multiply that number by .00023 to find the amount of Ca moles in the unknown solution then convert it to ppm? Or is my presumption incorrect?