A 3.5g sample of potassium chloride(KCl)is dissolved in 10mL of water.The resulting solution is the added to 60mL of a 0.5M CaCl2 soltion. Assuming that the volume are additive,calculate the molar concentration and %w/v of each ion present in final soltion.

Answer 1

mols KCl = grams/molar mass = approx 0.5 but that's just a close guess.
mols CaCl2 added = M x L = approx 0.03 or 0.03 mols Ca^2+ and 0.06 mols Cl^-.
Total K = 0.5 and total volume = 0.07L, then M K^+ = mols/L = ?

total Cl = 0.5 + 0.06 = 0.56 and total volume is 60+10 = 70 mL = 0.07L then M Cl = mols/L.
Note that you must go through each calculations to get a good number and not an approximation.

Answer 2

Thank you very much for your replies, DrBob :)