Does the molarity change with the volume? For example we did an experiment in lab with one trial containing 0.1 M KI at 100 mL and another with 50mL. So does the molarity (M) change with volume change?

Answer 1

No and yes. The answer to your question is no, the molarity is the same whether the volume is 50 mL, 25 mL, 100 mL or 1 L. However, since the volume of a liquid changes with temperature, the molarity DOES change as the temperature (and volume) changes. The point is that if we make up a solution that is supposed to be 1 M and it is in a 1 L volumetric flask and the temperature of the room is 35 C, the flask is calibrated to hold 1 L at 20 C (not 35 C); therefore, the solution will NOT be 1 M.