Question

Preparation of Solutions: Pre-laboratory Assignment Instructor Name Section Date 2. Prepare a written plan for making up 100.0 ml of a solution that is 0.100M in Ca2 ion using 2.00 M CaCl2H2O solution. 1. Prepare a written plan for making up 100.0 ml of 0.100 M KI solution. (Note the list of reagents and equipment provided in the background information). Include in your plan the exact amount of KI that you will need and the actual steps that you will take to prepare the solution. This plan should be drawn up on your own; your instructor will go over it with you before you proceed in the laboratory. -43-

Answer 1

The amount of KI needed = (100/1000) L * 0.1 mol/L = 0.01 mol

The molar mass of KI = 39.1 + 126.9 = 166 g/mol

Therefore, the mass of KI needed = 0.01 mol * 166 g/mol = 1.66 g

Question 2.

[CaCl2.2H2O] = [CaCl2]

M1V1 = M2V2

i.e. 2 M * V1 = 0.1 M * 100 mL

i.e. The volume of 2.0 M CaCl2.2H2O solution needed = 0.1*100/2 = 5 mL