Question

A.) A student removed 125.0 mL of a 0.155 M KCl solution? How many moles of KCl are in this sample?

B.) A student needed 0.761 mol of HCl. What volume (in L) of 0.131 M HCl solution would she take in order to get this sample?

Answer 1

volume of solution = 125ml = 0.125L

molarity of KCl        = 0.155M

no of moles of KCl   = molarity * volume in L

                                = 0.155*0.125 = 0.0194 moles

B.

    no of moles of HCl = 0.761 moles

molarity of HCl            = 0.131M

no of moles of HCl   = molarity * volume in L

    0.761                    = 0.131*volume in L

volume in L            = 0.761/0.131    = 5.81L >>>answer