Freezing Point Depression
Purpose
You will determine the freezing point of various solutions and correct the data to standard conditions of temperature and pressure (STP). To start this experiment you must first calibrate a thermometer. After that various chemicals are used to determine the freezing point depression of their solutions.
Proceedure
- Do not use any ammonium compounds or sugar. Read the MSDS sheets for the chemicals you are using.
- Mix up 50 milliliters of a one (1) molal solution of the chemical.
- Place the solution in an ice bath. The ice bath is made by filling a container larger than the beaker with ice and then pouring salt on the ice.r.
- As the ice melts more salt and ice should be added until the experiment is over. This occurs when the solution in the beaker starts to freeze after slow mixing. Record the temperature and compare it to the expected value.
- Clean the beaker and run the experiment with pure distilled water.
Conclusion
List the chemicals in order from the one that changed the temperature the least to the chemical that had the greatest effect. Next to the chemicals put the number of degrees difference compared to the original freezing point of water. The next column should have the accepted values. Give the percent error based only on the temperature difference.
- Do not use any ammonium compounds or sugar. Read the MSDS sheets for the chemicals you are using.
- Mix up 50 milliliters of a one (1) molal solution of the chemical.
- Place the solution in an ice bath. The ice bath is made by filling a container larger than the beaker with ice and then pouring salt on the ice.r.
- As the ice melts more salt and ice should be added until the experiment is over. This occurs when the solution in the beaker starts to freeze after slow mixing. Record the temperature and compare it to the expected value.
- Clean the beaker and run the experiment with pure distilled water.
Conclusion