Lab Report: Measurements and accuracy
By: Mandarin 10-‐2
Max (Jedsadakorn)
Mook (Pawida)
June (Chalini)
Jai (Thunyaluk)
Purpose
Section1: In order to calculate the density of a known substance (H2O), determine the precision and accuracy of different glassware items.
Section2: In order to determine the density of salt water solution using the most precise and accurate piece of glassware determined in section 1.
Hypothesis
In Hypothesis, we think that the graduated cylinder refer the most accuracy for the volume of water. On the other hand, water volume of the Small beaker seems to refer the least accuracy. The big beaker seems to be the most precise for the density of water, but the least precise would refer to Graduate Cylinder.
Materials -‐ Two 100mL beakers -‐ Two 50mL beakers -‐ One 10mL graduated cylinder -‐ One 10mL pipette with suction device -‐ Distilled water -‐ Saltwater solution A or B
Procedure
1. Weigh a dry 100mL beaker, a 10mL graduated cylinder and a 50mL beaker and record the mass for each on the data sheet. NOTE: Write down all the numbers since it tells us about the significant figures. 2. Fill another 100mL beaker with distilled water and measure its temperature. 3. To the best of your abilities, put 10mL of water in a) 100mL beaker, b) 10mL graduated cylinder, c) 10mL pipette. Record the volume for each one. 4. Weigh items a), b), and transfer c) into the previously weighed 50mL beaker and record the masses. BE CAREFUL!! 5. Do this three times for each glassware. 6. Use the result to calculate the density of water for each equipment. Compare the accuracy to a reference provided in this paper.
Data Table 1 Small Beaker (Pipette) Trial 1 2 3 Dry mass (g) 34.36 34.43 34.44 Mass with water (g) 43.6 45.5 45.86 Mass of water (g) 12.24 11.07 11.42 Volume of water (mL) 10 10 10 Density of water (g/mL) 1.22 1.1 1.14 Table2 Big Beaker Trial 1 2 3 Dry mass (g) 47.8 47.81 47.82 Mass with water (g) 57.95 56.94 55.68 Mass of water (g) 10.15 9.13 7.86 Volume of water (mL) 10 10 10 Density of water (g/mL) 1.01 0.91 0.79 Table3 Graduate Cylinder Trial 1 2 3 Dry mass (g) 29.35 29.34 29.35 Mass with water (g) 39.6 39.29 39.15 Mass of water (g) 10.25 9.95 9.8 Volume of water (mL) 10 10 10 Density of water (g/mL) 1.25
1 0.98
-‐ Which equipment showed highest accuracy? -‐ In what other situations would you use the other equipment? -‐ Why do you think your answer is not the same as the provided reference? -‐ What will happen if I slowly drop solutions A or B into a beaker with a substance whose density is 1g/mL? Will it float on top or sink to the bottom? Explain your answer.
Conclusion In conclusion, we concluded the result based on our hypothesis :Graduated cylinder is the equipment that have the highest accuracy because the result chart show the density of water on this equipment turned to be commonly the same amount. On the other hand, pipette is the equipment that has the least accuracy due to the result chart. The equipment that has the highest precise is the big beaker because the result density of all 3, nearly reach 1.0. In this statement, the result says that pipette has the least precise on the result above.