Freezing Point Depression of Aqueous Solution

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  • Topic: Chemistry, Sodium chloride, Sodium
  • Pages : 2 (365 words )
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  • Published : September 20, 2011
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Freezing Point Depression of Aqueous Solutions

Abstract: The purpose of this lab was to find the freezing point depression of 0.5M aqueous solution NaCl, distilled water, 0.5M aqueous solution of CaCl2, and unknown solution A. However, the teacher gave us values to do our experiment.


The objective of this lab is to understand how a solute depresses the freezing point of a solvent; also to comprehend the process of super cooling and to measure the freezing point of solutions and solvents.

The first part of the experiment is to observe the cooling curve for distilled water. The other two known solutions are sodium chloride and calcium chloride. We will be seeing the differences in their depression freezing points and how their “ionic makeup” effects how low the temperature goes. Lastly, we will be working with an unknown organic compound.

We will be making a freezing point depression apparatus by filling a liter beaker with ice and rock salt. Then we will be submerging a test tube with our compounds (NaCl, CaCl2, distilled water, and unkown organic compound) into the bath while attaching a LabPro unit to check the temperature over a certain amount of time. By using the LabPro device, we will be able to watch the correlation of the drop of temperature to the time it takes.

The chemicals used in this experiment were NaCl (0.5M), CaCl2 (0.5M), unknown organic compound, and distilled water. The equipment used was a LabPro unit device to measure the temperature and the time, 1L beaker, rock salt, ice, test tube with plug, test tube clamp, glass stirring rod and metal wire to stir the compound in the test tube. All the materials and regents were provided by PCC chemistry laboratory.

Graph for freezing point of 130 ml of water

Took 244 seconds to reach the freezing point of 0.2ºC

Graph for freezing point of 130 ml of 0.5M aqueous solution of NaCl


Took 244 seconds to reach the...
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