Calculate the molarities of each of the ions in a solution prepared by diluting 78mL of 4.5M Ca(ClO3)2 (aq) to 156mL with water. I am having trouble with this question. If anyone can show me what I need to do to solve this problem I will greatly appreciate it.

You first need to calculate the number of moles of each ion that you are adding to the water.

In the 78 mL of Ca(ClO3)2, can you work out the number of Ca^2+ ions and the number of ClO3^- ions?