posted by Jasmin on .
Calculate the new molarity if each of the following dilutions is made. Assume the volumes are additive.
(a) 52.3 mL of water is added to 27.1 mL of 0.124 M KOH solution
(b) 110. mL of water is added to 54.2 mL of 0.808 M NaCl solution
((please show work, thank u so much)
The easiest way to work with these type of calculations is to calculate the number of millimoles present, calculate the total volume and then work out the concentration.
Number of millimoles of KOH = N =
27.1 x 0.124 mmoles
Total volume after dilution = V =
52.3 ml + 27.1 ml
Thus new concnetration = N/V
The reason for working in mmoles is that if you work in moles a factor of 1000 appears, which cancels at the end.