Lab report CHM421 experiment 1

CHM421 ANALYTICAL CHEMISTRY -Laboratory report-

TITLE:

EXPERIMENT 1 (CALIBRATION OF VOLUMETRIC FLASK)

Experiment 1: Calibration of a Volumetric Flask Objective

1. To calibrate a used volumetric flask. 2. To determine the new calibration mark of the volumetric flask. Introduction

Volumetric flask is a glassware to measure the quantity of liquid solution in the experimental  procedure. Every volumetric flask that already used need to calibrate frequently to maintain the apparatus is in the best condition. The tolerance of error for a 100 mL volumetric flask is approximate ± 0.1 mL, if the volume of volumetric flask is exceed this tolerance the glassware need to be calibrate before used. To calibrate the 100 mL volumetric flask, the mass of a liquid is measured to know its density then the temperature of the liquid need to be determine first before start the calibration process. The density of water is different from the standard weights of the analytical balance, thus the mass obtain must be corrected for the buoyancy. The calculation for calibration need to be precise. The data will be converted to the volume of the apparatus at the temperature of calibration by dividing the liquid density and temperature. Then, the volume will be corrected based on the standard temperature of 20⁰C.

Discussion

This experiment are to calibrate the 100 mL volumetric flask that have already used in the laboratory. The new mark on the volumetric flask was determine after the calibrating which is 1.4163 mm above the actual line. During the experimental there’s a lot of error that can happen during handling the glassware that can affect the data obtain. There two type of error that can happen firstly, the human error. For the example is the meniscus error of the water during taking the reading of water in the volumetric flask. To overcome this error, while taking the volume of water make sure human eye is perpendicular with the meniscus to avoid the meniscus error. The instrumental error that can happen during this experimental is error occurs during measure on electronic weight balanced. Others error that can happen is the apparatus is not dry enough and cleaned in a proper way. The temperature of water will have a greater effect to the calibrating method because before start the experiment we need to measure the temperature of water about 15 minutes and refer the table 1 (volume for 1.00g of water at various temperature ). As the result for water temperature is about 30⁰C which the volume of 1.00g water is 1.0051 mL. Thus, the mass of water in the volumetric flask will multiply with 1.0051 mL (volume for 1.00 g of water) and obtained the volume of volumetric flask which is 99 .7210 mL. in the theory, if the volume of vol. flask is lower than 100, it need to add 5mm of water above the mark and the recalculated again its weight to ensure the accuracy of the measurements of a quantity’s actual volumes while precision of the volumes is the degree to which repeated measurement under unchanged conditions show the same results.in this experiment the new mark that obtain from this calibrating methods is 1.4163 mm above the old mark.

Conclusion

The new mark after calibrating the volumetric glassware is 1.4163 mm above the old mark where the temperature of water is 30⁰C. References

1. https://www.thoughtco.com/definition-of-calibrating-glassware-604658 2. https://www.bartleby.com/essay/Lab-report-calibration-of-volumetric-flask-PKJE4S43VJ