Experiment 3 Using Freezing-Point Depression to find Molecular Weight DONE.docx - LABORATORY REPORT Experiment 3 Using Freezing-Point Depression to Find

Experiment 3 Using Freezing-Point Depression to find Molecular Weight DONE.docx

This preview shows page 1 - 2 out of 7 pages.

LABORATORY REPORT Experiment 3 Using Freezing-Point Depression to Find Molecular Weight Name: __Emily Jaramillo_________________________ Date:__2/13/2017______________ Lab Partner’s Name: _Ilka Gomez__________________ Score: _________________ I. Introduction All substances whether a pure substance or solution contain a certain concentration of particles within them. Properties that are dependent upon the concentration of solute particles are called colligative properties. Colligative properties include vapor pressure lowering, freezing point depression, boiling point elevation and osmotic pressure. The concentration in relation to colligative properties can be expressed by finding the molality or the amount moles of solute per kilogram of solvent. Molality is used in relation to these properties because it is not dependent on temperature and uses the mass of the solvent. In this experiment we will be focused upon finding the molar mass of benzoic acid by using the resulting freezing point depression ( ΔT f = K f m ) Freezing point depression occurs when a solute and solvent are mixed together, and the measured freezing point is lower than that of the pure solvent by itself. In this lab we used the Vernier software as well as the temperature probe to record the data from both the pure lauric acid and the solution of benzoic and lauric acid and make the appropriate graphs of the cooling curves. The modifications in this experiment included using only 4 grams of lauric acid and 0.5 grams of benzoic acid. It was important to take in to consideration all safety precautions when performing this experiment. These precautions included wearing the appropriate PPE to avoid any skin contact with the acids used in the experiment as well as to prevent the severe eye damage caused by benzoic and lauric acid. It is also advised that all wires be kept away from the hot plate to avoid damaging equipment or causing a fire. The substances in the test tube should be mixed carefully with the temperature probe to avoid breaking the test tube and spilling its contents.
Image of page 1
Image of page 2

  • Left Quote Icon

    Student Picture

  • Left Quote Icon

    Student Picture

  • Left Quote Icon

    Student Picture