Colligative Properties

A truck de-ices a snow covered road

During snow storms, the roads become unsafe for drivers. In addition to plowing the roads to clear the snow, the snow plows must use a de-icer to eliminate any ice that is present. The most commonly used de-icer is salt. The truck in the image is using a chemical de-icer. Salt is a solute and chemical de-icers contain solutes. The solutes impact the properties of the solution. Both salt and chemical de-icers will melt the snow by changing the colligative properties of the frozen water. The colligative properties of solutions depend on the ratio of solute particles to solvent molecules. These properties do not depend on the type of molecule. In this topic, you will look at two colligative properties, freezing point depression and boiling point elevation.

Essential Question

• Why do particles in a solution change the colligative properties?