Independent variable mass weighed out of each unknown

This preview shows page 1 - 5 out of 6 pages.

Independent Variable: Mass weighed out of each unknown three samples
Speed of titration of each sample Number of moles used of MgSO 4 in each unknown sample Dependent Variable: Volume of EDTA used for titration Different color shades produced as the endpoint approached Percentages of MgSO 4 in each unknown sample Control: Concentration of EDTA Drop of Eriochrom black T indicator Volume of buffer solution Procedure: Qualitative observations: Purple-blue color as the titration is complete
Strong odor from buffer solution Eriochrome Black T indicator color Quantitative Observations: Mass of unknown sample= mass of weighing paper- mass of weighing paper with unknown Trial 1: 0.3933g-0.2458g=0.1475g Trial 2: 0.3887g-0.2456g=0.1431g Trial 3:0.3919g-0.2460g=0.1459g Volume of EDTA used: Vol. of initial EDTA – Vol. of final EDTA Trial 1: 50ml-41ml=9ml Trial 2: 41ml- 32ml=9ml Trial 3: 32ml-23.2ml= 8.8ml # of moles of EDTA used= Volume of EDTA in liters*concentration of standardized EDTA Trial 1: 9ml/1000= 0.009L*0.0459=4.131x E-4moles Trial 2: 9ml/1000= 0.009L*0.0459=4.131x E-4moles Trial 3: 8.8ml/1000= 0.0088L*0.0459=4.039xE-4moles # of moles of MgSO 4 in Erlenmeyer flask: # of moles of EDTA/1 Trial 1: 4.131x E-4moles /1= 4.131x E-4moles Trial 2: 4.131x E-4moles /1= 4.131x E-4moles Trial 3: 4.039xE-4moles/1=4.039xE-4moles Mass of MgSO 4 in the flask: # of moles of MgSO 4 in flask X molecular mass of MgSO 4 Trial 1: 4.131x E-4moles x 120.366g/mol= 0.04972g Trial 2: 4.131x E-4moles x 120.366g/mol= 0.04972g Trial 3: 4.039xE-4x 120.366g/mol=0.04862g % MgSO 4 in the unknown sample: X 100
Trial 1: X 100= 33.71% Trial 2: X 100= 34.74% Trial 3: X 100= 33.32% Average % MgSO 4 in unknown = 33.92% Standard deviation: = 0.7337 Graph,Tables: Unknown:49 Concentration of the Standardized EDTA solution: 0.0459 Trial Trial 2 Trial 3 Mass of weighing paper 0.2458g 0.2456g 0.2460g Mass of paper and unknown 0.3933g 0.3887g 0.3919g

  • Left Quote Icon

    Student Picture

  • Left Quote Icon

    Student Picture

  • Left Quote Icon

    Student Picture