Ashley Weber
Principles of Chemistry 2
Experiment 1
02/02/2015
Abstract:
Several experiments were performed to observe the colligative properties. This includes the freezing point depression, and osmotic pressure. Two ice baths were made, one with pure water, the other with salt water. The lowest temperature was then record for each bath and compared. The salt water had a lower freezing point than the pure water by 2 degrees which supports the hypothesis that solutions have a lower freezing point than pure water. The second property observed was osmosis pressure. This experiment used a 6 inch piece of dialysis tubing that was filled 2/3 full with light Karo syrup and tied off. Then it was completely submerged in a large glass bowl of room temperature distilled water. The dialysis tubing acts as a semi-permeable barrier and water passed through to inside the tube and over the next several hours, this act caused the tube to swell. Osmosis is where water moves from an area of high concentration to low concentration, therefore causing the tube to swell. The last experiment involved placing an egg in a jar of vinegar. After 24 hours, the shell of the egg completely disintegrated. Then the jar was rinsed and refilled with Karo syrup where the egg was submerged for 48 hours. This allows osmosis to take place where the water inside the egg leaves and moves outside where thereis a lower concentration of water. Thus, making the mass of the egg smaller.
This series of experiments takes a closer look at the colligative properties, specifically the freezing point depression and the osmotic pressure. Colligative properties is where the concentration of solute particles in a solution is what is important and not necessarily the chemical identity of the solute.
The first part of this experiment focuses on the freezing point depression. The freezing point depression is based on the idea that a solution freezes at a lower temperature than the freezing