Embedded Files
COLLIGATIVE PROPERTIES
COLLIGATIVE PROPERTIES
The following discussion and videos can be used to complete Virtual Experiment 27 laboratory assignment
The assignments that must be completed are:
The assignments that must be completed are:
Complete the pre laboratory writing assignment before coming to the class meeting.
Attempt the pre laboratory problems by completing the assignment or the pre laboratory problems quiz in Canvas before coming to the class meeting.
Using the class data and cooling curve graphs provided in the experiment to complete the calculations to determine the molar mass of the unknown substance added to the cyclohexane for ALL trials of Part I and Part II
Complete the laboratory report, show how to calculate the values used to determine the molar mass of the unknown added to cyclohexane.
Complete the conclusion paragraph for this experiment.
Pre laboratory assignments
Pre laboratory assignments
Complete the pre laboratory writing assignment in your laboratory notebook. The prewriting must be completed before the laboratory session begins. The writing should include a purpose/hypothesis of the experiment, a discussion or theory, a detailed step by step summary of the procedure explaining what data will be collected and how you will collect it. Data Tables or space to collect the data should be included within the procedure discussion. Look up any SDS on chemicals that you are not familiar.
Attempt the pre laboratory problems either as the document provided in the experiment or as the laboratory quiz in canvas before coming to the class meeting.
Procedure
Procedure
A small amount of pure cyclohexane will be cooled in a salt water ice bath and the temperature will be measure until the liquid has completely frozen into the solid state. The cyclohexane will be weighed and a small amount of unknown will be dissolved in the cyclohexane and cooled in a salt water ice bath. The data will be collected using the MicroLab program and the 528 MicroLab Laboratory Data System. The Cooling curve graphs will be interpreted to determine the freezing point of both the pure and the mixture.
Use the MicroLab program which can be downloaded at https://microlabinfo.com/products-1/software. Once the free program is downloaded, open the program and by importing the two data files, the graphs can be used to determine the freezing points of the pure cyclohexane and the mixture.
Data file for pure cyclohexane: https://drive.google.com/file/d/1njMg3Pfz6zwzfLTga9xMkmY46Qn057WQ/view?usp=sharing
Data file for mixture: https://drive.google.com/file/d/19OhKgpIwrok5fO6Yqp46lqTmCrLvKqg3/view?usp=sharing
Once the spreadsheet opens, download the file and save it. This file can be imported into Microlab and the freezing point determined from the graph. See the video on how to download and import the data into Microlab. To interpret the graph, look at the direction in the MicroLab document above or in the video below on how to interpret the data in the graph.
Print and include the above graphs in your report.
lab 27 introduction and calibration.mp4Introduction to the laboratory and calibration of the MicroLab thermistor probe.
Analysis of the data, results and graph for the video trial and class data.
lab 27 freezing point cyclohexane.mp4Cooling curve of the pure cyclohexane
lab 27 graph interpretation.mp4Interpretation of the collected temperature data to determine the freezing point of the pure cyclohexane.
lab 27 mixture prep.mp4Preparation of Mixture
see the pictures of the masses used to prepare this solution below.
lab 27 cooling curve for mixture.mp4Cooling curve of the mixture
Empty test tube with beaker
with cyclohexane
unknown A
cyclohexane with unknown
Analyze the video data in the graphs and add the video trial of this laboratory experiment to the class data using the mass data given above. Then using the class data with the following curves for Trial 6 and Trial 7, complete the calculations for all trials. If you analyze the graphs for the video trial, you do not need to analyze the graphs for Trial 6 or 7. Temperature time data to create the cooling curve for the video Trial for cyclohexane and for the mixture is available in the class data Google sheet on two separate tabs. Create the cooling curve for the video trial and determine the freezing points for the pure cyclohexane and the mixture.
Cooling curve of Pure Cyclohexane taken using
MicroLab and a temperature probe.
Cooling cuve of cyclohexane with ~0.5 grams of
an unknown substance in solution.
Molar Mass by Freezing Point Depression Lab Video Explanation
Molar Mass by Freezing Point Depression Lab Video Explanation
nathanjones0117
This lab shows the explanation for a freezing point depression lab using different chemicals with the same results - determination of the molar mass of an unknown.
Another example of a Freezing Point Lab
https://youtu.be/06-o_t5qyio
Calculating Molar Mass from Freezing Point Depression
Calculating Molar Mass from Freezing Point Depression
webpage-http://www.kentchemistry.com/links/Ma...
This short video shows you how to calculate the molar mass of a nonelectrolyte (van't hoff=1) using freezing point depression.
Example Question:
The freezing point of a solution that contains 1.00 g of an unknown compound, dissolved in 10.0 g of benzene is found to be 2.07oC. The freezing point of pure benzene is 5.48 oC. The molal freezing point depression constant of benzene is 5.12 oC /molal. What is the molecular weight of the unknown compound?
Report and Conclusion Paragraph
Report and Conclusion Paragraph
Complete the data and result tables, graphs, calculations and answer all required questions.
Complete a conclusion paragraph using the RERUNS method. A discussion of how to write a conclusion paragraph is given in Appendix D: How to Write a Formal Laboratory Report
Page updated
Report abuse