Introduction to Laboratory Glassware and Measurement (1)

Introduction to Laboratory Glassware and Measurement Makayla Pearson Section #012 Part A: Determination of water density using different glassware. Table 1: Density determination of water with different glassware Glassware Trial Volume of water (mL) Mass of water (g) Density (g/mL) Mean Density (g/mL) Standard Deviation (g/mL) Percent (%) Error (g/mL) Graduated Cylinder 1 2 3 49.00 mL 49.00 mL 49.00 mL 47.93 g 48.16 g 48.35 g 0.98 g/mL 0.98 g/mL 0.95 g/mL 0.97 g/mL 0.017 g/mL 2.827% Beaker 1 2 3 50.00 mL 50.00 mL 50.00 mL 23.96 g 24.44 g 25.27 g 0.48 g/mL 0.49 g/mL 0.51 g/mL 0.49 g/mL 0.015 g/mL 50.91% Erlenmeyer flask 1 2 3 50.00 mL 50.00 mL 50.00 mL 40.08 g 41.43 g 42.04 g 0.82 g/mL 0.83 g/mL 0.84 g/mL 0.82 g/mL 0.01 g/mL 17.85% Volumetric flask 1 2 3 50.00 mL 50.00 mL 50.00 mL 49.66 g 49.72 g 49.75 g 0.99 g/mL 0.99 g/mL 0.99 g/mL 0.99 g/mL 0 g/mL 0% Calculations :  Density (m/v) o Graduated Cylinder  47.93 g/49.00 mL  = 0.968163265 g/mL  ≈ 0.97 g/mL o Beaker  23.96 g/50.00 mL  = 0.4792 g/mL  ≈ 0.48 g/mL o Erlenmeyer Flask  40.80 g/50.00 mL  = 0.816 g/mL  ≈ 0.82 g/mL o Volumetric Flask  49.66 g /50.00 mL  = 0.9932 g/mL  ≈ 0.99 g/mL

 Mean Density - (Σm/ Σv) o Graduated Cylinder  Σ 144.55 g / Σ 147 mL  = 0.98333 g/mL  ≈ 0.98 g/mL o Beaker  Σ 73.67 g/ Σ 150 mL  = 0.491133333 g/mL  ≈ 0.49 g/mL o Erlenmeyer Flask  Σ 123.55 g / Σ 150 mL  = 0.82366667 g/mL  ≈ 0.82 g/mL o Volumetric Flask  Σ 149.13 g/ 150 mL  =0.9942 g/mL  ≈ 0.99 g/mL  Standard Deviation σ = √(∑(x−¯x) ( x − x ¯ ) 2 /n)) o Graduated Cylinder o 0.0006 g/mL ÷ 2 g/mL o = 0.0003 g/mL o √0.0003 g/mL o = 0.017320508075689 g/mL o ≈ 0.017 g/mL o Beaker o 0.00046666666666667 g/mL ÷ 2 g/mL o = 0.00023333333333333 g/mL o √0.00023333333333333 g/mL o 0.015275252316519 g/mL o ≈ 0.015 g/mL o Erlenmeyer Flask o 0.0002 g/ml ÷ 2 g/mL o = 0.0001 g/mL o √0.0001 g/mL o = 0.01 g/mL o Volumetric Flask o 3.6977854932235E-32 g/ mL ÷ 2 o = 1.8488927466117E-32 o √1.8488927466117E-32

c. A volumetric flask can be used for volume measurement and holding chemicals. It will always be the most accurate when performing volume measurements because of its singular neck tick. Otherwise, it is only used to hold chemicals. Part B: Determination of the nature of an unknown metal. Table 2: Unknown metal block density using volume displacement Trial Mass of metal (g) Initial water volume (mL) Final water volume (mL) Water volume displaced (mL) Density of Metal (g/mL) Mean Density (g/mL) Standard deviation (g/mL) Percent (%) Error) 1 35.22g 26.00 mL 30.00 mL 4.00 mL 1.174 g/mL 1.174 0 0% 2 35.22g 26.00 mL 30.00 mL 4.00 mL 1.174 g/mL x x x 3 35.22g 34.00 mL 38.00 mL 4.00 mL 1.174 g/mL x x x Calculations :  Volume Displaced o Trial 1  30.00 mL – 26.00 mL = 4.00 mL o Trial 2  30.00 mL – 26.00 mL = 4.00 mL o Trial 3  30.00 mL – 26.00 mL = 4.00 mL  Density (m/v) o Trial 1  35.22 g/ 30.00 mL

 = 1.174 g/mL  Percent Error- Percentage Error = ((Estimated Number – Actual Number)/ Actual number) x 100. o Trial 1  | 1.174 - 1.174/ 1.174 | x 100  = | 0/ 1.174 | x 100%  =|0| x 100  = 0% o Trial 2  | 1.174 - 1.174/ 1.174 | x 100  = | 0/ 1.174 | x 100%  =|0| x 100  = 0% o Trial 3  | 1.174 - 1.174/ 1.174 | x 100  = | 0/ 1.174 | x 100%  =|0| x 100  = 0% Table 3: Unknown metal block density using the ruler Trial Mass of Metal (g) Diameter (cm) Height (cm) Density (g/mL) Mean Density (g/mL) Standard Deviation (g/mL) Percent (%) Error 1 35.22 g 1.00 cm 5.00 cm 8.962 g/mL 8.962 g/mL 0 0% 2 35.22 g 1.00 cm 5.00 cm 8.962 g/mL x x x 3 35.22 g 1.00 cm 5.00 cm 8.962 g/mL x x x