CHEMISTRY 101L DATA SUMMARY EXPT 2 Name Seth Bollenbecker Lab Section 407 Scientific Measurements and Error Table 1 Mass Trials Average Mass and Standard Deviation of Weighing Bottles Sample Weighing bottle with lid Partner s Weighing bottle with lid Weighing bottle with lid on different balance Mass g Trial 1 72 793 69 989 Mass g Trial 2 72 793 69 689 Mass g Trial 3 72 793 69 689 Mass g Trial 4 Average Mass g Standard Deviation g 72 794 69 688 72 793 69 764 0 00045 0 13005 72 779 72 776 72 775 72 779 72 777 0 00206 Table 2 Glassware Marking Observations Glassware TC or TD Calibration Temperature oC Volume Graduation mL 100 mL beaker 400 mL beaker 10 mL graduated cylinder 100 mL graduated cylinder 100 mL volumetric flask 250 mL volumetric flask 5 mL graduated pipet 15 mL volumetric pipet 50 mL buret TD TD TC TC TD TD TD 20 20 20 20 20 20 20 20 50 1 10 100 250 1 15 1 Table 3 Various Glassware Water Measuring Techniques to Determine Accuracy Glassware Mass of water 400ml beaker g Mass of Water g 100 mL beaker 10 mL graduated cylinder 100 mL graduated cylinder 5 mL graduated pipet 25 mL volumetric pipet 50 mL buret 178 735 179 492 178 735 180 526 179 822 179 618 23 823 24 580 23 823 25 614 24 910 24 706 Table 4 Volume Trials Average Volume and Standard Deviation of Multiple Sets of Glassware Trail 1 is the glassware of my experiment while the other trials represent other group s data sets Average Glassware Volume Trial Volume Trial Volume Trial Volume Trial Volume mL 1 mL 24 98 24 68 23 92 25 72 2 mL 23 42 24 42 23 11 28 72 3 mL 17 44 24 45 23 43 24 65 4 mL 21 66 24 05 24 54 25 86 Standard Deviation mL 2 817 0 2257 0 5397 1 508 21 88 24 40 23 75 26 24 25 01 24 93 24 98 24 83 24 94 0 06834 24 81 28 42 25 26 28 10 26 65 1 624 100 mL beaker 10 mL g c 100 mL g c 5 mL graduated pipet 25 mL volumetric pipet 50 mL buret Table 5 Masses of Vials and Their Contained Water and Pasteur Pipet Calibration Accuracy Vial I 15 063 15 905 0 842 0 845 Vial II 15 021 12 659 0 638 0 641 Vial III 14 791 15 544 0 753 0 756 Vial IV 15 115 16 034 0 919 0 923 Mass of Empty Vial g Mass of Vial Water g Mass of Water g Volume of Water mL Average Volume mL Classmate Standard Deviation mL Classmate Percent Error Classmate 0 21 0 12 57 08 Average Volume mL Personal Standard Deviation mL Personal Percent Error Personal Discussion Conclusion 0 09 0 13 144 44 Write a conclusion to your findings in Experiment 2 Be sure to discuss specifics of your experiment in scientific measurement Refer to the UNC writing Center at http writingcenter unc edu resources handouts demos specific writing assignments scientific reports section 22 for some help This should be no longer than 2 paragraphs Experiment 2 revealed many things about the glassware utilized in the lab Table 1 began by showing that different factors such as temperature drafts and the actual scale could make a difference in the weight of the same object Discrepancies all in reference to Table 1 between trial 3 72 793 g and trial 4 72 794 g while weighing the same container on the same scale and also trail 3 72 775 g and trial 4 72 779 g on another scale mean that environmental factors do play a part Glassware markings were observed in Table 2 with TC to contain and TD to deliver recorded as well as the 20 C marking for proper measuring temperature and measurement increments on each piece of lab glass The accuracy of each piece of glassware was tested and recorded in Table 3 The most accurate piece was the 25 mL volumetric pipet being that it measured out 24 910 g of water closest to the 25 g accuracy target of the experiment The least accurate pieces were the 100 mL beaker and the 100 mL graduated cylinder both of which measured 23 823 g of water the farthest from the 25 g accuracy target Table 4 incorporated data from other groups to show how human error less accurate measuring glasses and alternate weighing apparatuses can easily affect measurements Standard deviation the amount of aberration between different values was very high for the 100 mL beaker 2 817 and the 50 mL buret 1 624 when four group s data was compared This is a result of the nonspecific volume graduation on the 100 mL beaker 20 mL and the inability to easily stop water from flowing out of the 50 mL buret The average volumes throughout the glassware ranged from 21 88 mL in the 100 mL beaker to 26 65 mL in the 50 mL buret revealing that measurements collected by different groups on different electronic scales can have very different results that may not average out to be near the intended 25 mL ideal measurement Table 5 was used to identify accuracy of the Pasteur pipet calibration that each group was instructed to conduct The group that switched their Pasteur pipet with my group had a much higher accuracy with 57 08 error verses my group s 144 44 error They also only experienced a standard deviation of 0 12 mL whereas my group had a 0 13 mL standard deviation Based on this data the other group s calibration method was more effective than my group s method