Introduction:
The purpose of this lab is to learn about the calibration of a thermometer. In addition, we also investigated the boiling point of an unknown liquid to determine its identity.
Chemical Responsibility:
1. Make sure to use glycerine (lubricant) and a towel to safely insert the thermometer into the rubber stopper.
2. Carefully operate the Bunsen burner and make sure to use rubber gloves when handling the boiling water of beaker
3. Always wear goggles at all times and avoid contact with the unknown liquids
4. After the lab is done, pour the unknown liquid into a container labeled “Waster Experiment 1 Boiling Point Unkowns” and throw away any broken glass in the proper broken glass container
Report Sheet: (see attached sheet)
Sample Calculations: (see attached sheet)
Discussion of Results:
In the beginning of the lab, we calibrated the thermometer. The temperature of the ice water bath was 1.0 °C and the temperature of boiling water was 95 °C. The thermometers errors at 0 °C is +1.0 °C and at 100 °C the error is -5.0 °C. This information was used to calibrate the thermometer for the temperature measurements later.
After receiving the unknown solution, I measured the boiling point twice to determine its identity. The two measured boiling points of my unknown substances are
79 °C and 78 °C. But after the corrected boiling point using the thermometer corrections, the boiling points of the unknown substances are actually 84 °C and
83 °C.
The average of the two boiling points are 83.5 °C. And based on the prelab questions, I can determine that the unknown liquid is isopropyl alcohol. The boiling point of isopropyl alcohol is 82 °C, which is the closest of the three different unknown liquids that we were working with.
Post Lab Questions: (see attached sheet)
Conclusion:
In this lab, I calibrated my thermometer and found the error of the temperature recordings. And then I proceeded to record the boiling point of my unknown substance and determined that it was isopropyl alcohol.