4. Discussion

4.1 Key findings

From this project, we have found that impurities such as salt brings down the freezing temperature of a solution. This process is known as Freezing Point Depression. As seen in the graph, the average freezing point of the solution decreases as the mass of salt in the concentration of water increases, showing an indirect proportion relationship between the mass of salt in the concentration of water and average freezing point of the solution.

4.2 Explanation of key findings

Our goal for this experiment is to find out whether or not the mass of impurities such as table salt (NaCl) in the concentration of water will affect the freezing point of a solution. Through our experiments, we found out that when impurities are added to a solution, it would decrease the freezing point of the solution. This can be seen from Figure 1 which shows the average freezing point of the solution decreasing as the mass of the salt in the concentration of the water increases. This process of lowering the freezing point of a solution is called Freezing Point Depression which is a colligative property, a property that depends on the number of solute particles are in the solvent. Other research and experiments conducted have also shown the same results as our experiments. This is reliable as through our research, we have found out that by combining these three factors—molality, m, van't Hoff factor, i, and molal freezing-point-depression constant, Kf—into an equation that predicts how much the freezing point of a solvent will decrease, ΔT, when a certain amount of solute is added to the solvent, thus providing us a theory which will be a gauge on whether our results are reliable or not.

4.3 Evaluation of hypothesis

Our hypothesis was the higher amount of dissolving chemicals in water, the lower the freezing point of water. As we have tested out in our experiment, it is proven that the higher amount of dissolving chemicals in water, the lower the freezing point of water.

4.4 Areas for improvement

From our experiment, we found out that we need to have things planned out before the experiments. Also, we have to manage our time well in order to be able to complete our experiments and collect results to be used for analysis. We could have used insulators to prevent the ice from melting too quickly and through research we found out that sawdust is the best insulator that is easily available and cheap. We could also have done our experiments with different types of solute other than water such as cooking oil and detergent so that we can see if other impurities can also affect the freezing point of other solutes.