FACULTY OF RESOURCE SCIENCE AND TECHNOLOGY DEPARTMENT OF CHEMISTRY STK 1201 – PRACTICAL PHYSICAL CHEMISTRY 1 EXPERIMENT NO

FACULTY OF RESOURCE SCIENCE AND TECHNOLOGY
DEPARTMENT OF CHEMISTRY
STK 1201 – PRACTICAL PHYSICAL CHEMISTRY 1
EXPERIMENT NO :
1
TITLE OF EXPERIMENT:
GLASSWARE CALIBRATION
DATE OF EXPERIMENT 28/09/2018
GROUP MEMBERS & MATRIC NUMBERS ZAIDA AFIFAH BT MOHD ZAINI (65276)
NOR ADILLA BT ABDULLAH (65011)
NUR HANANI ‘AMIRAH BT MOHD YAZID
(65066)
LAB FACILITATOR ASSOC PROF DR. CHIN SUK FUN
REPORT DUE DATE 12/10/2018
INTRODUCTION
Volumetric glassware is generally made to specification limits, particularly regarding to the accuracy of calibration. Calibration is still required although many effort have been made in the construction to ensure that it is accurate and within its specified tolerance. Calibration helps to determine relationship between the analytical response and the analyte concentration (Cruz J.V, 2014). Volumetric glassware is also a class of glass vessels that calibrated to contain or deliver certain volume of substances. Calibration of laboratory glassware can be carried out with the use of distilled water, and an accurate balance. Using the known density of water, the volume contained in or delivered by a piece of glassware may be accurately determined using equation below:
?= mvThere are three types of glassware that typically used in laboratory experiment. These tools are used extensively when performing gravimetric and titrimetric analysis. The first one is volumetric flask. Volumetric flask are calibrated to contain an exact volume of solution when the solution level is exactly at the mark on the neck of the flask which means the bottom of the meniscus should lie exactly at this mark.
Next, pipettes are calibrated to deliver an exact volume of liquid or solution from one container to another. There are two types of pipettes: volumetric pipette and Mohr pipette. Volumetric pipette have only one calibration mark while Mohr pipettes, also known as graduated pipette are used to deliver fractional volumes of solution. These pipettes have graduated marks throughout the length of the pipettes therefore they are far less accurate than volumetric pipettes. To use volumetric pipette, simply draw in liquid to the mark. Also, it is better to overshoot the mark and let the liquid drain from the pipettes until the bottom of the meniscus lies exactly on the calibration mark. The liquid in the tip should not be blown-out after transferring the liquid.

Lastly is burette. Burettes allow you to accurately deliver volumes of liquid that cannot be measured by volumetric pipettes or micropipettes. Make sure to open the stopcock to fill the tip with water and no air bubbles and read the initial reading before starting the experiment. After transferring the liquid, make sure to tap the tip to let the last drop drain. The proper use of burettes is essential for accurate titration analyses. The quality of the experiment obtained from these tools depend heavily on the care taken in calibrating and proper ways in using each instrument.

OBJECTIVES
The purpose of this experiment is to study the different and the relationship of several types of glassware. Then, to determine the measurement of the actual volume contents of volumetric flask, pipette and burette glassware. We also want to investigate the mass of the liquid the glassware will hold, and to divide this mass of liquid by the reference density of the liquid at specific temperature obtaining the corresponding volume of the liquid. Lastly, the aim of this experiment is to study the accuracy and precision of some commonly used glassware then discuss the importance of calibrating them.

MATERIAL AND METHOD
REAGENT
-Distilled water
APPARATUS
-Volumetric pipette
-Burette
-Beaker
-Volumetric flask
-Thermometer
-Retort stand
PROCEDURE
The temperature of water is recorded to the nearest °C using the thermometer. Table 1.1 summarizes the density of water at various temperatures.

Temperature (?) Density (g/mL)
20 0.998203
21 0.997992
22 0.997770
23 0.997538
24 0.997296
25 0.997044
26 0.996783
27 0.996512
28 0.996512
29 0.995944
30 0.995646
Table 1.1 Density of water at various temperatures.

A)Pipette calibration
1.A volumetric pipette is selected to calibrate.

2.A small empty beaker is placed on the analytical balance and tare the balance.

3.The pipette is filled to the calibration mark with distilled and drained the water into the beaker on the balance.

4.The balance is tare and repeated this procedure twice.

5.The water volumes from the masses recorded is calculated.

B)Burette calibration
1.The burette is filled with distilled water and any bubbles is forced out of the tip. We make sure that the burette drained without leaving drops on the walls. The meniscus is adjusted to be between 0.00 and 100 mL and the burette tip is touch to a beaker to remove the suspended drop of water. The initial reading of the burette is recorded.

2.A clean and dry Erlenmeyer flask is weighed and the mass is recorded to the nearest 0.0001 g.
3.5 mL of distilled water is drained nominally into the weighed Erlenmeyer flask. We allowed about 30 seconds for the film of liquid on the walls to descend before we recorded the reading of the burette.

4.The flask is weighed again to determine the mass of water delivered.

5.The process are repeated for 2 more times.

6.The procedure is repeated by using 10 mL, 15mL, 20 mL and 25 mL.

7.The true volume of water delivered is determined by using the density information.

C)Volumetric flask calibration
1.A dry and clean volumetric flask is selected to calibrate.

2.The mass of the empty, dry volumetric flask with stopper is recorded.

3.The volumetric flask is filled with distilled water to the mark. Then, the mass is recorded.

4.The procedure is repeated twice and the actual volume of distilled water contained is calculated.

RESULT
Based on the data collected, we can calculate the apparent mass, true mass, average volume of water and the standard deviation for each calibration of pipette, burette and volumetric flask.

The mass of air displaced in the water transferred is 0.0012 times the volume of water transferred so, the calculated mass of air has to be included to apparent mass to get the true mass of water transferred (g) as shown:
Trial 1:
0.0012 gmL X 24.853 g = 0.0298 m L
0.0298 m L + 24.853 g = 24.883 g
Trial 2:
0.0012 gm L X 24.880 g = 0.0299 m L
0.0299 m L + 24.880 g = 24.910 g
Trial 3:
0.0012 gmL X 24.754 g = 0.0297 m L
0.0297 m L + 24.754 g = 24.788 g
Average volume of water transferred (mL) is calculated by adding all three actual volume of water transferred in every trial and divided by three.

24.853 + 24.880 + 24.758 (mL) = 74.4913 =24.830 mL
To calculate the standard deviation for this pipette calibration based on the data that we have, we use this formula to find them:

X = actual volume of water transferred (mL)
µ = mean (average volume of water transferred)
n = total number of trial
Find (x-x)2 for each trial,
Trial 1: (24.853-24.774)2= 5.76×10-4
Trial 2: (24.880-24.774)2= 2.601×10-3
Trial 3: (24.758-24.774)2= 5.625×10-3
Add all value of each trial and divide by n (n=3)
5.76×10-4 + 2.601×10-3 + 5.625×10-3 = 8.802×10-32 = 4.401×10-3 ? = ±0.066
The same goes to the next calibration which is burette calibration. We need to calculate the actual volume of water transferred (mL) true mass of water (g), average volume of water transferred (mL) and standard deviation for this calibration. Here’s some calculation of a few calibration of burettes:
Calibration of burette- 5 mL
Actual volume of water transferred (m L):
Trial 1:
0.997538 g/m L X 4.996 g = 4.984 mL
Trial 2:
0.997770 g/m L X 5.008 g = 4.997 mL
Trial 3:
0.997770 g/m L X 4.945 g = 4.934 mL
True mass of water (g):
Trial 1:
0.0012 g/m L X 4.996 g = 5.9952×10-3 m L
5.9952X10-3m L + 4.996 g = 5.002 g
Trial 2:
0.0012 g/m L X 5.005 g = 5.9964×10-3 m L
5.9964X10-3 m L+ 5.005 g = 5.014 g
Trial 3:
0.0012 g/m L X 4.945 g = 5.9208×10-3 m L
5.9208X10-3 m L + 4.945 g = 4.951 g
Average volume of water transferred (m L):
(4.984 + 4.997 + 4.934)(mL) ÷ 3 = 4.972 m L
Standard deviation:
1.44×10-4+6.25×10-4+1.444×10-32 ? = ±0.033
Calibration of burette- 10mL
Actual volume of water transferred:
Trial 1:
0.997538 g/mL X 10.007 g = 9.982 m L
Trial 2:
0.997770 g/mL X 9.783 g = 9.761 m L
Trial 3:
0.997779 g/mL X 9.944 g = 9.922 m L
True mass of water (g):
Trial 1:
0.0012 g/mL X 10.007 g = 0.01198 m L
0.01198 m L + 10.007 g = 10.019 g
Trial 2:
0.0012 g/mL X 9.783 g = 0.0117 m L
0.0117 m L + 9.783 g = 9.795 g
Trial 3:
0.0012 g/mL X 9.944 g = 0.0119 m L
0.0119 m L + 9.944 g = 9.956 g
Average volume of water transferred (m L):
(9.982 + 9.761 + 9.922)÷ 3 = 9.888 m L
Standard deviation:
8.836×10-3+0.016129+1.156×10-32 ? = ±0.114
Calibration of burette- 25m L
Actual volume of water transferred (m L):
Trial 1:
0.997770 gmL X 24.923 g = 24.867 m L
Trial 2:
0.997770 gmL X 24.957 g = 24.901 m L
Trial 3:
0.997770 gmL X 24.966 g = 24.910 m L
True mass of water (g):
Trial 1:
0.0012 gmL X 24.923 g = 0.0298 m L
0.0298 m L + 24.923 g = 24.953 g
Trial 2:
0.0012 gmL X 24.957 g = 0.0299 m L
0.0299 m L + 24.957 g = 24.987 g
Trial 3:
0.0012 gmL X 24.966 g = 0.0299 m L
0.0299 m L + 24.966 g = 24.996 g
Average volume of water transferred (m L):
(24.867 + 24.901 + 24.910)÷3 = 24.893 m L
Standard deviation:
6.76×10-4+6.4×10-5+2.89×10-42 ? = ±0.023
For the last part is volumetric flask calibration. We repeated the same processes to calculate the actual volume of water transferred (mL), true mass of water (g), and average volume of water transferred (mL) and their standard deviation, ?.

Actual volume of water transferred (m L):
Trial 1:
0.997770 gmL X 99.182 g = 98.961 m L
Trial 2:
0.997770 gmL X 98.833 g = 98.613 m L
Trial 3:
0.997770 gmL X 98.964 g = 98.626 m L
True mass of water (g):
Trial 1:
0.0012 g/mL X 99.182 g = 0.1188 mL
0.1188 mL + 99.182 g = 99.301 g
Trial 2:
0.0012 gmL X 98.833 g = 0.1183 m L
0.1183 m L + 98.833 g = 98.951 g
Trial 3:
0.0012 gmL X 98.846 g = 0.1184 m L
0.1184 m L + 98.846 g = 98.964 g
Average volume of water transferred (m L):
(98.961 + 98.613 + 98.626)(m L)÷ 3 = 98.733 m L
Standard deviation:
0.051984+0.0144+0.0108162 ? = ±0.196
DISCUSSION
Usually, everyone makes mistakes when we are doing experiment especially quantitative experiment which is involved the calculation and the reading of volume correctly. Basically, all volumetric glassware is calibrated with markings used to determine a speci?c volume of liquid to varying degrees of accuracy (Walker, 2011). Calibration is the common procedure by which an expressed measure, for example, the volume of a container is checked for precision and accuracy.
For the glassware calibration experiment, we divided into three part which is pipette calibration, burette calibration and volumetric flask calibration.

Part A: Pipette calibration
Volumetric pipette is calibrated to deliver an exact volume of liquid or solution. Volumetric pipette has only one calibration mark. First of all, we put a small empty beaker on the analytical balance and tare the balance to obtain the mass of empty beaker which is 47.057 g for the first trial. Next, we filled the pipette to the calibration mark with distilled water and we ensured that the tip of the pipette does not touch the bottom of the beaker as the tip is very fragile. Then, we drained the water into the beaker. However, we make sure that a small amount of solution remained at the tip of pipette by carefully touch the tip to the side of beaker. As the pipette is specifically calibrated, so that this should not affect the amount of water that we transferred. After that, the mass of water transferred is recorded.
Then, water temperature is recorded by using the thermometer which is 22°C. The 22°C of water temperature indicated the density of water which is 0.997770 g/mL. To minimize the error during calibration, we tare the balance again and repeat this procedure twice.

Part B: Burette Calibration
Burette allows you to deliver volumes of liquid accurately that cannot be measured by volumetric pipette or micropipettes. The proper use of burette is essential to accurate titration analyses. Firstly, we filled the burette with distilled water. To obtain a good result, we got rid the air bubbles by letting the solution drain until the air bubbles are removed. Next, we weighed a clean and dry Erlenmeyer flask and the mass is recorded to the nearest 0.0001 g which is 51.412g.

After that, 5 mL of distilled water is drained nominally into the weighed Erlenmeyer flask. Drain water slowly until the meniscus is at the 0.00 mL mark. The tip of the burette needed to touch the side of a beaker to remove the drop hanging from the tip. To avoid the errors during the reading of initial and final reading scale of burette, we used a piece of white paper to see the scale of burette clearly and the crucial part is we took the reading at the particular part of meniscus and always measure this part. Then, we weighed the flask again to determine the mass of water delivered.
Basically, we repeated the process for trial 2, and trial 3 while we redo all the procedure by changing to 10 mL, 15mL, 20mL and 25mL. By obtaining the information of density, we managed to determine the true volume of water delivered.

Part C: Volumetric flask calibration
Volumetric flasks are calibrated to contain an exact volume of solution when the solution level is exactly at the mark on the neck of the flask which the bottom of the meniscus should lie exactly at this mark. We weighed the dry volumetric flask with stopper and the mass is recorded. Next, we filled the volumetric flask to the mark with distilled water and the mass of volumetric flask after filled with distilled water is recorded. To calculate the mass of the liquid contained or dispensed by the glassware will be measured and the corresponding volume, we need to record the temperature of distilled water to find out the density. The same goes to part C which we repeated all the procedure twice and calculated the actual volume of distilled water contained.

Generally for our result, we did not managed to obtain an accurate result due to certain error that could be parallax error or systematic error. However, we managed to obtain a very precise result overall. The mass of the liquid contained or dispensed by the glassware will be measured and the corresponding volume calculated using the density of the liquid. However, a relatively small change in temperature causes a change in the liquid’s volume and thus its density.

CONCLUSION
In summary of the experiment, we had studied the different and the relationship of several types of glassware. We also had determined of the actual volume contents of the glassware by technique of calibration. Next, we investigated the mass of the liquid the glassware would hold, and divided this mass of liquid by the reference density of the liquid at specific temperature which is 22? that obtain the corresponding volume of the liquid. Lastly, the accuracy and precision of pipette, burette and volumetric flask had been study while discussed the importance of calibrating them.

POST-LAB QUESTIONS
Pipettes are used to transfer liquid sample and they are rinsed with a small amount of the sample after transfer. Calculate the % error that will be produced with pipette of the 1 mL, 5 mL and 10 mL if each pipette retains 5 drops of water after use. Assuming the volume of one drop of water is 0.05 mL.

Answer
Volume of 5 drops retain, 5 x 0.05 mL = 0.25 mL
– % error of 1 mL of pipette,
0.25 mL1.00 mL x 100 = 25%
– % error of 5 mL of pipette,
0.25 mL5.00 mL x 100 = 5%
– % error of 10 mL of pipette,
0.25 mL10.00 mL x 100=2.5 %It is important to ensure that no air bubbles are captured at the stopcock of the burette when the initial reading is recorded. If 0.5 mL of air bubbles is present in the burette, what is the % error that will be generated in 10 mL, 20mL and 40 mL of sample when the air bubbles are released?
Answer
– % error in 10 mL of burette,
0.5 mL10.00 mL x 100 = 5%
– % error in 20 mL of burette,
0.5 mL20.00 mL x 100=2.5%- % error in 40 mL of burette,
0.5 mL40.00 mL x 100=1.25%REFERENCES
Lab report calibration of volumetric flask. (2016 Apr 28). Retrieved from https://studymoose.com/lab-report-calibration-of-volumetric-flask-essayCalibration of volumetric glassware. Retrieved from http://www.cameron.edu/~keithv/quant/cal_vol.htmlWalker J.P (2012). General Chemistry 2 Labs Using Argument-Driven. Retrieved from
http://www.webassign.net/question_assets/tccgenchem2l1/glassware/manual.htmlCruz, J.V. (23 July 2014). Calibration of Volumetric Glassware. Retrieved from
www.academia.edu/29578028/Calibration_of_Volumetric_Glassware_Procedure_ExperimentAdorna, J. A. (2013 June 2). Retrieved on 5 October 2018 from https://www.scribd.com/doc/188639745/Experiment-2-Calibration-of-Volumetric-GlasswareDATA SHEET
A) Pipette Calibration
Trial 1 Trial 2 Trial 3
Water temperature, t(?)22.0 22.0 22.0
Mass of empty beaker (g) 47.057 47.057 47.057
Mass of beaker with distilled water (g) 71.910 71.937 71.815
Apparent mass of water transferred (g) 24.853 24.880 24.754
True mass of water transferred (g) 24.883 24.910 24.788
Density of water at t ? (g/mL) 0.997770 0.997770 0.997770
Actual volume of water transferred (m L) 24.798 24.825 24.699
Average volume of water transferred (m L) ± standard deviation 24.774 ± 0.066
B) Burette Calibration
5mL Trial 1 Trial 2 Trial 3
Water temperature, t (?) 23.0 22.0 22.0
Initial reading of burette 0.50 5.50 10.50
Final reading of burette 5.50 10.50 15.50
Nominal volume of water transferred (m L) 5.00 5.00 5.00
Mass of empty Erlenmeyer flask (g) 51.412 51.480 51.431
Mass of Erlenmeyer flask with water (g) 56.408 56.488 56.376
Apparent mass of water (g) 4.996 5.005 4.945
True mass of water (g) 5.002 5.014 4.951
Density of water at t ? (g/m L) 0.997538 0.997770 0.997770
Actual volume of water transferred (m L) 4.984 4.997 4.934
Correction of nominal (labelled) volume (m L) 0.016 0.003 0.066
Average volume of water transferred (m L) ± standard deviation 4.972 ± 0.033
10mL Trial 1 Trial 2 Trial 3
Water temperature, t (?) 23.0 22.0 22.0
Initial reading of burette 15.50 25.50 35.50
Final reading of burette 25.50 35.50 45.50
Nominal volume of water transferred (m L) 10.00 10.00 10.00
Mass of empty Erlenmeyer flask (g) 51.452 51.428 51.511
Mass of Erlenmeyer flask with water (g) 61.459 61.211 61.455
Apparent mass of water (g) 10.007 9.785 9.944
True mass of water (g) 10.019 9.795 9.956
Density of water at t ? (g/m L) 0.997538 0.997770 0.997770
Actual volume of water transferred (m L) 9.982 9.761 9.922
Correction of nominal (labelled) volume (m L) -0.019 0.239 0.078
Average volume of water transferred (m L) ± standard deviation 9.888 ± 0.114
15mL Trial 1 Trial 2 Trial 3
Water temperature, t (?) 22.0 22.0 22.0
Initial reading of burette 2.50 17.50 32.50
Final reading of burette 17.50 32.50 47.50
Nominal volume of water transferred (m L) 15.00 15.00 15.00
Mass of empty Erlenmeyer flask (g) 51.499 51.529 51.444
Mass of Erlenmeyer flask with water (g) 66.468 66.487 66.374
Apparent mass of water (g) 14.969 14.958 14.930
True mass of water (g) 14.987 14.976 14.948
Density of water at t ? (g/m L) 0.997770 0.997770 0.997770
Actual volume of water transferred (m L) 14.936 14.925 14.897
Correction of nominal (labelled) volume (m L) 0.064 0.075 0.103
Average volume of water transferred (m L) ± standard deviation 14.919 ± 0.020
20mL Trial 1 Trial 2 Trial 3
Water temperature, t (?) 22.0 22.0 22.0
Initial reading of burette 0.50 20.50 0.0
Final reading of burette 20.50 40.50 20.00
Nominal volume of water transferred (m L) 20.00 20.00 20.00
Mass of empty Erlenmeyer flask (g) 51.457 51.501 51.450
Mass of Erlenmeyer flask with water (g) 71.432 71.389 71.416
Apparent mass of water (g) 19.975 19.888 19.966
True mass of water (g) 19.999 19.912 19.990
Density of water at t ? (g/m L) 0.997770 0.997770 0.997770
Actual volume of water transferred (m L) 19.930 19.844 19.921
Correction of nominal (labelled) volume (m L) 0.070 0.156 0.079
Average volume of water transferred (m L) ± standard deviation 19.898 ± 0.047
25mL Trial 1 Trial 2 Trial 3
Water temperature, t (?) 22.0 22.0 22.0
Initial reading of burette 20.00 0.00 25.00
Final reading of burette 45.00 25.00 50.00
Nominal volume of water transferred (m L) 25.00 25.00 25.00
Mass of empty Erlenmeyer flask (g) 51.500 51.457 51.555
Mass of Erlenmeyer flask with water (g) 76.423 76.414 76.521
Apparent mass of water (g) 24.923 24.957 24.966
True mass of water (g) 24.953 24.987 24.996
Density of water at t ? (g/m L) 0.997770 0.997770 0.997770
Actual volume of water transferred (m L) 24.867 24.901 24.910
Correction of nominal (labelled) volume (m L) 0.133 0.099 0.090
Average volume of water transferred (m L) ± standard deviation 24.893 ± 0.023
C) Volumetric Flask Calibration
Trial 1 Trial 2 Trial 3
Water temperature, t (?) 22.0 22.0 22.0
Mass of empty volumetric flask (g) 63.103 63.408 63.400
Mass of volumetric flask with distilled water (g) 162.285 162.241 162.246
Apparent mass of water (g) 99.182 98.833 98.846
True mass of water (g) 99.301 98.951 98.964
Density of water at t ? (g/m L) 0.997770 0.997770 0.997770
Actual volume of water transferred (m L) 98.961 98.613 98.626
Average volume of water transferred (m L) ± standard deviation 98.733 ± 0.196