David Millard
Partner: Naomi Bryner
Experiment 1: Calibration of Glassware
Introduction:
Students will be immersed in different types of glassware. The glassware will be calibrated with the temperature of the room and the most reliable pieces of glassware will be determined.
Procedure:
Calibration of Pipets

Weigh a clean, dry weigh bottle (beaker) five times and record the empty weight.

With a 1mL pipet, fill the pipet to the 1mL mark and place the volume in the weigh bottle, reweigh the weigh bottle and record the weight.

Repeat the last step four more times.

Repeat the procedure of filling a pipet and transferring the volume for a
2mL and a 5mL pipet.

Average the raw data for each pipet and determine the standard deviation and relative standard deviation.
Calibration of Volumetric Flasks

Weigh a clean, dry 10mL volumetric flask, record the weight.

Fill the flask to the mark and reweigh it, recoding the weight.

Repeat four more times.

Repeat the procedure for a 25mL and a 50mL volumetric flask also.

Average the raw data for each flask and determine the standard deviation and relative standard deviation.

Data:
Calibration of Pipets
Weight Bottle Dry
Trial 1
Trial 2
Trial 3
Trial 4
Trial 5
Average
Standard Deviation
Relative Standard Deviation
Mass
55.8933g
55.8928g
55.8932g
55.8929g
55.9924g
55.9129g
0.0444
0.0795%
1mL pipet
Trial 1
Trial 2
Trial 3
Trial 4
Trial 5
Average
Standard Deviation
Relative Standard Deviation
Mass with Water Mass of Water
56.8855g 0.9922g
56.8825g
56.8807g
0.9897g
0.9875g
56.8694g
56.8821g
56.8800g
0.0437
4.5178%
0.9765g
0.8897g
0.9671g
2mL pipet
Trial 1
Trial 2
Trial 3
Trial 4
Trial 5
Average
Standard Deviation
Relative Standard Deviation
Mass with Water Mass of Water
57.8814g
57.8842g
1.9881g
1.9914g
57.8771g
57.8294g
57.8839g
57.8712g
1.9839g
1.9365g
1.8915g
1.9583g
0.0435
2.2224%

5mL pipet
Trial 1
Trial 2
Trial 3
Trial 4
Trial 5
Average
Standard Deviation
Relative Standard Deviation
Mass with Water Mass of Water
60.8816g 4.9883g
60.8879g
60.8663g
4.9951g
4.9731g
60.8762g
60.8689g
60.8762
0.0492
0.9905%
4.9833g
4.8765g
4.9633g
Calibration of Volumetric Flasks
10mL Volumetric
Trial 1
Trial 2
Trial 3
Trial 4
Trial 5
Average
Standard Deviation
Relative Standard Deviation
25mL Volumetric
Trial 1
Trial 2
Trial 3
Trial 4
Trial 5
Average
Standard Deviation
Relative Standard Deviation
50mL Volumetric
Trial 1
Trial 2
Trial 3
Trial 4
Trial 5
Average
Standard Deviation
Relative Standard Deviation
Dry Mass Mass with Water Mass of Water
13.7268g
13.7269g
23.6441g
23.6233g
9.9173g
9.8964g
13.7270g
13.7270g
13.7269g
13.7269g
23.6570g
23.7081g
23.6717g
23.6608g
0.0318
0.3201%
9.9300g
9.9811g
9.9448g
9.9339g
Dry Mass Mass with Water Mass of Water
20.0924g
20.0924g
20.0924g
20.0923g
20.0923g
20.0924g
45.0183g
44.9724g
45.0027g
44.9849g
44.9858g
44.9928g
0.0178
0.0716%
24.9259g
24.8800g
24.9103g
24.8926g
24.8935g
24.9005g
Dry Mass Mass with Water Mass of Water
48.5099g
48.5098g
48.5097g
48.5097g
48.5095g
48.5097g
98.1217g
98.1206g
98.1026g
98.1920g
98.1834g
98.1441g
0.0408
0.0821%
49.6118g
49.6108g
49.5929g
49.6823g
49.6739g
49.6343g

Calculations:
Finding an average
T
1
+ T
2
+ T
3
5
+ T
4
+ T
5
= Average
Example
55.8933g + 55.8928g + 55.8932g + 55.8929g + 55.9924g
= 55.9129g
5
Mass of water
Mass with water − Mass of dry weighbottle
Example
I56.8855g − 55.8933g = 0.9922g
Standard Deviation
Example
√
(m
1
− avg) 2 + (m
2
− avg) 2 + (m
3
− avg) 2 + (m
4
Trials − 1
− avg) 2 + (m
5
− avg) 2
√
(0.992g − 0.9671g) 2 + (0.9897g − 0.9671g) 2 + (0.9875g − 0.9671g) 2 + (0.9765g − 0.9671g) 2
4
+ (0.8897g − 0.9671g) 2
= 0.0437
Relative Standard Deviation
Standard Deviation
∗ 100
Total Average
Example
0.0437
0.9671
∗ 100 = 4.518%

Conclusion:
Based on the above data the 5mL pipet had the least percentage of error, but the greatest standard deviation. The small percentage is caused by the fact that there is more volume being used compared to the 1mL pipet which had a percentage of 4.51%. These values were inversely related. The volumetric flasks varied from the pipets. The 25mL volumetric flask had the lowest standard deviation as well as the lowest percentage of relative standard deviation. Human error was a very large part in this experiment. If the meniscus wasn’t cut by the fill line on the pipet or volumetric flask at the same area every time, a different amount of water would have been transferred or collected. Also, after drying the weigh bottle after each pipet, the weigh bottle may not have been completely clean, there could have been some trace amount of water left in the beaker which added to the next mass.
Post Laboratory Questions:
1.
Explain using calculations and words whether it is better to use 20, 49, or 56mL of solution from a fifty mL buret.
Based off of our calculations, the 49 mL of solution would be most favorable in a 50 mL buret.
The larger the amount of solution in the buret would help lessen the error of the standard deviation. The data we collected with the transfer pipets showed this correlation. The 1 mL pipet had the largest error where the 5 mL pipet had the smallest percentage.
2.
M
1
V
1
= M
2
V
2
M
2
M
1
V
1
V
2
=
{[0.1012M(±0.0025)][43.56mL(±0.89)]}
50mL(±0.05)
0.0025
0.1012
0.89
∗ 100 = 2.47%
43.56
∗ 100 = 2.04%
0.05
50
∗ 100 = 0.1%
M
2
=
{[0.1012M(±2.47%)][43.56mL(±2.04)]}
50mL(±0.1)
= 0.088M(e
4
) e
4
= √(2.47) 2 + (2.04) 2 + (0.1) 2 = 3.27%
0.0327 ∗ 0.088 = 0.0029
0.088M(±0.0029) 0.088M(±3.27%)