The Depression Constant

In this lab we were able to determine the freezing temperature of lauric acid. Then we determine the freezing temperature of a mixture of lauric acid and benzoic acid. We were able to calculate both the freezing point depression of the mixture and the molecular weight of benzoic acid from our data. First we worried about our safety so we put on our goggles. Next we retrieved of the materials needed for the experiment. Then we set up our ring stand and clamp on the test tube. After this was complete we were able to get the pure lauric acid from the hot bath and we put it in our test tubes. Without a second thought or hesitation we quickly paced across the room back to our lab station. When we got there we put the temperature probe in the hot water. After we saw the temperature probe was reaching its maximum, we inserted the test tube in a beaker of water at room temperature. We stirred the probe for 10 long minutes and we saw that the test tube dropped in temperature and eventually that hot liquid solidified to a degree. After that we wiped off the probe and rinsed out the test tube until sterile then we were able to do the entire experiment over but with a lauric acid- benzoic acid mixture. There may have been some error from the time you received the acids to the time you start the experiment. The longer it takes to take the acid over would mean there would be lower starting temperatures for the experiment. Another error that could happen would be that you do not stir the temperature probe. If you do not do that then the acid's temperature will abase much faster, ruining the true lesson of the experiment. I found it to be interesting that we could actually use the freezing point to find the molecular weight in a lab setting like ours. I always thought we would need the technology that is only found in government labs. I feel that we have successfully calculated the freezing point depression of the mixture and we were able to calculate the molecular weight of benzoic acid with ease.

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