Boiling point: To find the boiling point of Isopropyl Alcohol I put about 1 mL of it in the test tube. Then I attached the thermometer to the test tube with a rubber band(make sure the thermometer bulb is lined up with the end of the test tube).
After that I made a water bath with a beaker and put in the test tube with the thermometer. I then used a burner and a burner stand to heat up the water bath. When the alcohol starts to boil I extinguish the burner and wait until the last bubble emerges from the test tube and recorded the temperature. Do 2-3 trials and take the average. Melting point: First crush the Acetamide and make it to a powder. Make the same water bath as done before when finding the boiling point of Isopropyl Alcohol. Once the Acetamide starts melting extinguish the burner. Let it cool and recrystallize. Repreat the process 2-3 times and take the average temperature.
Questions
A. Why is it useful to know the melting point/ or boiling point of a substance? Finding the melting/ boiling point of a substance is useful when doing filtrations. For example, if there was a mixture that has water and two solids (one of them being acetamide), we can just boil the mixture and let it reach approximately over 81 degrees Celsius, we would know that the acetamide melted into a liquid and we can filter out the solid that is left. Afterward let the rest of the mixture cool and the acetamide crystalize and then repeat the process of filtering out the acetamide. B. How would you determine the melting of a substance whose melting point is higher than 100-Celsius degrees?
The Essay on Test Tube Physical Chemical Record
Abstract: This lab assignment is to observe certain substances and observe its physical and chemical changes in different environmental conditions. We first observed its physical properties, such as physical state and color and recorded it on paper. Then we did different types of experiments on some of the substances and observed the chemical changes. Some of the chemical changes where ...
You would either use a melting point apparatus or instead of using a water bath you would use another type of liquid that had a higher boiling point then water. C. What would be the effect of increasing the amount of crystals in the capillary tube? No effect because the melting point is still going to be the same no matter how many crystals there are. D. List sources of error and explain how they would affect your end results. The biggest source of error in my opinion is human error – not recording the temperature exactly at the last bubble came out.
Conclusions
In my opinion, the lab went pretty well. There was less then 1% error in both of the experiments with Isopropyl Alcohol and Acetamide. During the experiment I found that the Isopropyl Alcohol boiling point was average approximately 82.3-celsius when the actual is 82.4-celsius. The Acetamide melting point was average approximately 81.7-celsius when the actual is 81-celsius. I feel like doing three trials really helped because it reduced the percent error, which allowed me to get the best results possible.
