The freezing point of a substance is when the substance turns from a liquid to a solid. The freezing point of a solvent can be decreased by adding a solute and making a solution, which is a freezing point depression. From knowing the temperature difference between a pure solvent and a mixture, it is possible to find the molar mass of the solute.
After each of the solids were completely dry, each was placed into a MelTemp device. The temperature at which each solid began to melt and completed melting was recorded.
The freezing point depression constant for water that was experimentally determined in this analysis was 0.0479 °C/m, which was derived from the slope of the trend line in Figure 4. This is significantly lower than the constant stated in the literature of 1.86 °C/m.1 The freezing point temperature determined via cryoscopy should have been much lower in the high sucrose concentration solutions.
In order to fulfil the labs purpose, the lab was split into two parts. The first part consisted of measuring and determining the freezing point depression of the solution water. The second part consisted of measuring and determining the freezing point depression of a solution that consisted of water and an unknown solute.
The specific property observed in this lab was the freezing point depression caused by the additives. This is the change in the freezing point between a standard solvent and said solvent with added solutes. This changes the entropy of the system, making the properties change somewhat, lowering the freezing point itself with the addition of more solute. Hence, the term ‘freezing point depression’.
Through our data acquisition on day one our predicted values for the change in temperature of our NaCl solution in water was slightly off. This was most likely due to recording the freezing temperature sometime after the precise moment of the solution freezing. However, we predicted that as we doubled our concentration of NaCl in solution the freezing point depression would also double which is consistent with our results. Through our day one experiments we were able to better understand the ability of NaCl as a deicer by understanding how the freezing point depression changes based on concentration. We could further test these results by testing with different concentrations of NaCl.
Purpose: The purpose of this laboratory was to gain an understanding of the differences between the freezing points of pure solvent to that of a solvent in a solution with a nonvolatile solute, and to compare the two.
melting produced a drop in pipette readings. For each gram of ice that melted, the volume change
The reaction "ICE" table demonstrates the method used in order to find the equilibrium concentrations of each species. The values that come directly from the experimental procedure are found in the shaded regions. From these values, the remainder of the table can be completed.
The freezing point is the temperature at which a substance transfers from its liquid phase to a solid. Through comparison of the freezing points of a pure solvent (stearic acid), with those of a dilute solution, the molar mass of unknown solutes may be obtained. Water in its solid and liquid phase obtains a dynamic equilibrium (as their molecules convert between such phases at equal rates). Equilibrium can be disrupted through change in temperature or the addition of a solute. Increasing the temperature causes molecules to accelerate, prompting energy to be shifted to the solid surface and escape to the liquid phase. Increasing the quantity of solute in the liquid phase displaces some solution molecules that would have (if unimpeded) interacted
This science fair project is important in ways that people should use to form certain things that could help people see that there is a better conservation of goods. This could help better the community by using different substances from housing areas then put them to use. The freezing point Is determined by how much of particles were broken down In the mixture. When its in freezing point the potential of that solution will be equal in both states. Also this project would solve certain issues people may have with freezing water in different ways. This could help scientist figure out what and how the freezing point of water could help preserve the goods that we use in everyday life. In everyday life people freeze stuff but what if there was a way to freeze things without using just coolness but other tempatures. Also if people would consider using salt and sugar to tell if there is a difference I’m tempature it could spark a new way to do things in this economic system we have.
The first part of the experiment focused on finding the melting point range of known substances, Trans-cinnamic acid and Urea. The Trans-cinnamic acid had a melting point range of 133.0-135.8℃. Urea had a melting point range of 132.5-135.8℃. However, when a 50/50 mixture was created of the two substances, the melting point range was 98.8-132℃, 40 degrees less than the two known substances. This is due to an impurity of the 50/50 mixture. Each substance was acting as an impurity to the other substance. The expected range for Trans-cinnamic acid was 132-135℃ and Urea had an expected range of 132-133℃. Trans-cinnamic acid and Urea are similar compounds but lack identical structure, causing their combined melting point range to be lower than what
The objectives of this lab are, as follows; to understand what occurs at the molecular level when a substance melts; to understand the primary purpose of melting point data; to demonstrate the technique for obtaining the melting point of an organic substance; and to explain the effect of impurities on the melting point of a substance. Through the experimentation of three substances, tetracosane, 1-tetradecanol and a mixture of the two, observations can be made in reference to melting point concerning polarity, molecular weight and purity of the substance. When comparing the two substances, it is evident that heavy molecule weight of tetracosane allowed
It is suspected that the freezing point is 64.1oC. Due to the short temperature plateau, It is difficult to determine if the freezing point occurs at during the interval (6:00-6:10). However, it appears to be have been the most reasonable determination for freezing point in comparison to the rest of the plot.