Topics: Freezing-point depression, Water, Amount of substance Pages: 2 (613 words) Published: October 28, 2014

Colligative Properties & Osmotic Pressure
Peter Jeschofnig, Ph.D. Version 42-0149-00-01
Lab Report Assistant This document is not meant to be a substitute for a formal laboratory report. The Lab Report Assistant is simply a summary of the experiment’s questions, diagrams if needed, and data tables that should be addressed in a formal lab report. The intent is to facilitate student’s writing of lab reports by providing this information in an editable file which can be sent to an instructor Observations & Questions for Part 1 Record your observations and your time and temperature data in tables. Use one table for the pure water and one table for the salt solution. Data Table 1: Pure Water and Salt Solution

Seconds Distilled H20
Room temp Distilled H20 Ice bath Saltwater
Room temp Saltwater Ice bath
0 30 60 90 120 150 180 210 240 270 300 330 360 390 420 450 480 510 540 570 600 630 660 Make two graphs of your data. On one graph plot the data from the pure water. On the other graph plot the data from the salt solution. On both plot temperature on the y-axis and time on the x-axis. A. Record the freezing point of the pure water and the freezing point of the salt solution. B. How do these two freezing points compare? C. What are some practical applications of freezing point depression, boiling point elevation, and vapor pressure lowering? Questions - Part 2

A. To what biological structure is the dialysis bag comparable? How is it similar? How is it different? B. In biological systems if a cell is placed into a salt solution in which the salt concentration in the solution is lower than in the cell, the solution is said to be hypotonic. Water will move from the solution into the cell, causing lysis of the...
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