Potassium Chloride Lab Report

Discussion

The ideal Van't Hoff factor for potassium chloride is 2, because the compound dissociates into its ions, K+ and Cl-. The greater the Van't Hoff factor means the more a compound lowers the freezing point temperature of the solvent it dissolves in. For a liquid to freeze it must form a lattice, a three-dimensional arrangement of particles that make up a crystalline solid, and the presence of solute particles interferes with the ability of the solvent particles to form a lattice. To compensate the system must be brought to an even lower temperature to freeze, and the more particles that are present within the solvent, the larger that freezing point depression becomes.3 Thus, the obtained value of 2.05 means that potassium chloride lowered

This was displayed in table 1, where the final temperatures of the water are lower compared to the initial temperatures, showing that the potassium chloride took heat energy away from the 20 mL of water. Endothermic deicers work slower than exothermic deicers, because endothermic deicers require warmer temperatures to dissolve, which makes them inferior when environmental temperatures are very low. Additionally, exothermic deicers will release energy as heat when the compounds dissociate, consequently, melting snow and ice faster.4 Furthermore, when comparing the enthalpy of dissolution of potassium chloride to magnesium chlorides value of -270, the most exothermic value in table 2, potassium chloride is shown to be a significantly worse deicer. Magnesium chloride being notably exothermic means that the compound can dissolve at low temperatures and releases copious amounts of heat

The enthalpy of dissolution for potassium chloride came out to be 8.73 kJ/mol, which indicates that the process was endothermic. Since the dissociation of potassium chloride is endothermic, it requires heat to dissolve, which makes it a low preforming deicer in very cold temperatures. Potassium chloride costs $8.99 per lb and compared to the lowest cost deicer sodium chloride, which costs $2.09 per lb, potassium chloride was not cost efficient. The environmental impacts are due to the chlorine component of each deicer. There are various negative health effects induced by chlorine that appear in animals and organisms in water and soil environments. However, all potential deicers have the same relative environmental impact. When all characteristics of the potential deicers are taken into consideration, the best road deicer was calcium