Describe the three freezing points. Is there a relationship between the amount of solute in the solution and the freezing temperature? Yes, the more solute the colder the temperature is B. What are some practical applications of freezing point depression? The longer the time, the colder it gets Data Table 4.
A graph for the data was also set up with time on the x axis in .5 second intervals and temperature on the y axis. The first task required the freezing point of pure p-xylene be determined. This was done by pipetting approximately 2ml of p-xylene into a polypropylene test tube. The dry thermistor probe was inserted into the p-xylene test tube which was then inserted into an ice water bath. The temperature probe was used to stir the p-xylene and ensured an accurate reading.
Do an initial Benedict's test on the 15% glucose/1% starch and the beaker solutions for glucose by putting some of the solution and a roughly equal amount of blue Benedict's solution in a test tube, placing the test tube in boiling water for 90 seconds, and observing whether or not the solution changes color from blue. 3. Form a bag out of dialysis tubing by tying off one end, putting in enough 15% glucose/1% starch solution to fill it halfway, and tying off the other end leaving the other half of the bag void of anything (even air). Write down the solution's color. 4.
5mL of acidified water will be measured, using a graduated cylinder, and will be transferred to the R tube, and will be immediately vigrously mixed with the reactants. Once the solution turns to an orange or red-brown color, a pipet will be used to quickly remove 30 drops of the solution, then transferred to the C tube, and the mixing will resume until the solution is close to room temperature. The solution will be filtered into the P tube, and the solution that is left in the R tube should be washed three times with 1mL of acidified water each time. The water should then be poured into the P tube, leaving the solid in the R tube. Using a test tube holder, heat the R tube over the Bunsen burner, moving the tube in a circular motion until all the water has evaporated.
First I made a water bath by filling the 100 mL beaker with cool tap water. I then placed crushed ice in the 100 mL beaker so the water level was just below the top of the beaker. I sprinkled a little salt in the ice water and mixed it well. I then filled the test tube half full with distilled water and set the test tube in the 24 well plate. I inserted the digital thermometer into the test tube and took reading every 30 seconds until the readings remained constant.
Materials: 3 beakers Thermometer 3 Alka-Seltzer tablets Stopwatch Mortar and pestle Source of hot water Ice cubes Graph paper Procedures: Hot water- Run water from the hot tap until it is hot as possible Fill beaker with 80 mL of hot water Use thermometer to take temperature of water. Record in data table. Remove 1 Alka-Seltzer tablet from package Drop into the water. Measure the time it takes for the tablet to completely dissolve. BE READY WITH THE STOPWATCH.
Part 1: Scemario 4 Carmen conducted an experiment to determine whether salt added to a cup of water affects its freezing point (the temperature at which it freezes). After some research, she hypothesized that the greater the amount of salt dissolved in the water, the lower the temperature at which the water freezes. Water samples were prepared containing equal quantities of water at the same starting temperature. Each sample received a different amount of salt and was placed into a freezer. The length of time it took for each sample to freeze was recorded as shown below.
Sac #1 placed into beaker #1 with distilled water, sac #2 placed into beaker #2 with 40% glucose solution and so forth. 3. Before analyzing, we had to allow sacs to remain undisturbed in the beaker for 1 hour. 4. After 1 hour we boiled a beaker of water on the hot plate (for Benedict’s and AgNO3 test).
Title: 1pt Stoichiometry Of A Precipitation Reaction 2. Procedure: 2pt (Write the procedure in your own words after you have read the lab manual) Put on goggles the weigh 1.0 of CaCl*2H2O and put it in 100ml beaker. Add 25 mil of water and stir. I will then use stoichmetry to figure out how much Na2CO3 I will need for a full reaction. I will weigh this and put it in a separate cup.
Lab Report 13: Ionic Reactions A product of Hands-On Labs, Inc. Authored by Peter Jeschofnig, Ph.D. Modified by Pamela Lee Hill, Ph.D., on Marvh, 2012 Review the safety materials and wear goggles when working with chemicals. Read the entire exercise before you begin. Take time to organize the materials you will need and set aside a safe work space in which to complete the exercise.