Laboratory Experiment: Measuring Precision and Accuracy of Equipment, Study notes of Theatre

Download Laboratory Experiment: Measuring Precision and Accuracy of Equipment and more Study notes Theatre in PDF only on Docsity! Introduction This experiment was done to test the precision and accuracy of the equipment in the laboratory. Precision is the quality of being precise, and accuracy is the ability of a measurement to match the actual value of the quantity being measured. In this experiment it was assumed that the balance was accurate. In order to obtain the correct results in this experiment one equation was used. The equation is density mass Volume  . Experimentation The first experiment was set up with a 125 mL Erlenmeyer flask, 50 mL flask, 250 mL flask, 100 mL beaker, weighing scale, pipet, buret, and distill water. The first procedure was to weigh the 250 mL flask and 100mL beaker empty on the weighing scale and then record the measurements in the lab notes. Next step was to use the 50 mL flask and fill it up with distill water, and then poured the 50 mL water into the empty 250 mL flask. The next step would be to measure the mass of the water. After recording the measurements in the lab book, repeat the same process two more times, but with different equipment. The second procedure was used with 100 mL beaker, pipet, and buret. Using 40 mL of distill water in a 100 mL beaker we measured the weight of the empty beaker and the weight with distill water, and then record our results. From there the 100 mL beaker with distill water was poured into the buret by using a pipet to make measurement more accurate. Then we used the density of water (1g) along with the weight of a drop of water to figure out the volume of a drop of water. The second experiment was set up with a 4 x 3 ½ inch paper, sand, small metal spatula, 50 mL flask, and weighing scale. The first procedure is to measure a 1 gram of sand. In order to measure sand, the first thing to do is weight the sand with a weightless material, which was paper. By placing the paper on the weighing scale we used the spatula to carefully scoop out sand to make our measurements precise. Once the weighing scale showed a range of 1g, the measurements were then recorded in the lab notes. The same procedure was trailed three times for observation. The third experiment includes a 600 mL beaker and distill water. The first procedure was to measure the 600 mL beaker empty and then pour in 75 mL of distill water. The 600 ml beaker with distill water was placed on top of the weighing scale for measurements, and then recorded. This procedure was processed 2 more times for comparison. The last experiment was to measure liquid with a graduated cylinder. The equipment that was used is a graduated cylinder, weighing scale, and distill water. The first procedure was to measure the graduated cylinder empty and record weight. Next is to pour 10 mL of distilled water into the graduated cylinder and weight them together for measurements. The same process was trailed 2 more times, but with different weighing scales. Results Table 1: Volume & Mass Measurements of Water Equipment Volume (mL) Mass 1 (g) Mass 2 (g) Mass 3 (g) 125 mL Flask 50 46.39 46.78 43.1 100 mL Beaker 40 33.96 33.22 32.35 1 mL Pipet 1 0.938 0.884 0.94 50 mL Buret 1 1.33 1.6 1.34 Table 2: Densities for Different Measurements of Sand Density 1 (g/mL) Density 2 (g/mL) Density 3 (g/mL) Average Density (g/mL) 0.928 0.936 0.862 0.908 0.849 0.831 0.8088 0.829 0.938 0.884 0.940 0.921 1.33 1.60 1.340 1.42 Table 3: Volume & Mass Measurements of 1 Drop of Water Volume (mL) Mass (g) Drop of Water 0.0251 0.025 to be 2.35 percent error. When measuring the volume and mass of a drop of water, the mass was found to be 0.025g. With the use of the actual density of water (0.997 grams per milliliter), the volume of a drop of water was found to be 0.025 milliliters. Various trials were made in order to find exactly 1 gram of sand. The average mass of 1 gram came out to be 1.005 grams. The 1.005 grams produced a 0.50 percent error. This error was largely due to the inaccuracy of the scales. The margin of error for the scale was ±0.0005 grams. The procedure that was found to be the best for finding the mass of 1 liter of water when a scale is not capable of measuring such a large amount was dimensional analysis. With the use of dimensional analysis it was far easier and less time consuming to find the mass of 1 liter of water than the other methods. With the use of dimensional analysis, it was calculated that 1.00 kilogram of 9.00% sodium chloride (NaCl) solution will be necessary to prepare 10.0 kilograms of 0.900 mass percent (NaCl). From our results in the lab, it was found that the graduated cylinder was the best piece of equipment that could be used when measuring volumes of liquids. Any percent error in this lab is attributed to various things. Among them, there exists the margin of the error for the equipment. Also, the room in which the scales were in had many people coming and going, therefore the air in the room was in constant movement, making the scales change the mass values continuously. Conclusion Overall this experiment helped show that accuracy and precision are important aspects when performing chemistry labs. It was found, through various trials of the experiment, that the graduated cylinder is the best piece of equipment to use when measuring volumes. The graduated cylinder had the smallest margin error and proved to be the easiest and best piece of equipment to use.