Experiment #2 Analysis of Magnesium Purpose: determine amount of ...
Experiment #2 Analysis of Magnesium Purpose: determine amount of magnesium in a pill 300 enzymes so far need magnesium for function. No magnesium metal occurs naturally. Required Daily Allowance (RDA) of Mg is 0.30.4 g Best sources are coffee, tea, leafy green vegetables Those with a deficiency take Mg pills I. A. Find x and y. xMg2+ + yEDTA4 Mgx((EDTA)y)
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1) Put around 100 mL of 0.01 M EDTA stock solution in a clean beaker. 2) Prepare a buret for EDTA solution. a. Get a funnel and place in buret. b. Make sure bottom is closed. c. Fill around 1/4 with solution. d. Stop buret at top with finger (WITH GLOVES) and invert it to wash the insides. e. Pour out into slop jar. 3) Fill buret with EDTA. 4) Put about 100 mL of 0.01 M Mg stock solution in a clean beaker. 5) Prepare a 2.5 mL volumetric pipette for Mg. 6) Get a pipette pump, put it on the volumetric pipette, and pump with Mg solution. 7) Invert to wash the pipette and put waste in slop jar. 8) Prepare 100 mL volumetric flask for H2O. 9) Pipette 25 mL of Mg stock solution into volumetric flask. (USE PIPETTE PUMP) 10) Dilute to the mark with water (comes from the white tap). (If you pass the mark, you must start over) Calculate Magnesium solution CiVi = CfVf (0.01)(25) = x(100) Cf = 0.0025 M I. B. Titration 1) 2) 3) 4) 5) 6)
Put around 25 mL of NH3 buffer in a small beaker. Cover with a watch glass. Pipette 25 mL (use pump) of Mg stock solution into an Erlenmeyer flask. Add 1 dropper of buffer (check for a pH of 10 with pH paper) TF adds EBT indicator. YOU WANT A WINERED COLOR. Record the initial volume on the buret to two decimals.
7) Slowly add the EDTA to the Mg stock solution in the Erlenmeyer flask until it is blue. (DON’T OVER TITRATE) [You can add white paper under it to see the color better] {PURPLE IS VERY CLOSE} 8) Record the final volume on the buret to two decimal places. 9) Repeat I. B. using a fresh 25 mL sample of Mg stock solution. I. C. Repeat I. B. but using the Mg solution you prepared. In calculations, x/y = (CMgVMg)/(CEDTAVEDTA) CMg = 0.01 stock, or 0.0025 your solution VMg = 0.025w ff L Goals; Calculate average x/y, standard deviation of x/y, 95% confidence interval x/y II. Get a pill 1) 2) 3) 4) 5) 6) 7)
Weight pill to 2 decimals. Crush pill with mortar and pestle. Weight out about 0.1 g of crushed powder and record weight. Place in a 250 mL beaker. Add 40 mL of 1.5 M HCl. Stir to dissolve. If solution is not clear, it has to be filtered. a. Get a filter flask, a b funnel, a cover thingy, and filter paper. b. Clamp down. c. Attach to vacuum. d. Turn on vacuum. 8) Transfer filtrate to a 100 volumetric flask. 9) Add H2O to the mark. III. Titrate at least 2 fresh 25 mL samples of Mg pill solution as before. ***May need 23 droppers of buffer to get pH 10*** Data Analysis: What is the mass of Mg in the pill? MMg Pill = (x/y)((CEDTAVEDTA)/VMg Pill)(0.1 L)(24.30g/mol)(mpill/mpowder)[pwoiep
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1) Put around 100 mL of 0.01 M EDTA stock solution in a clean beaker. 2) Prepare a buret for EDTA solution. a. Get a funnel and place in buret. b. Make sure bottom is closed. c. Fill around 1/4 with solution. d. Stop buret at top with finger (WITH GLOVES) and invert it to wash the insides. e. Pour out into slop jar. 3) Fill buret with EDTA. 4) Put about 100 mL of 0.01 M Mg stock solution in a clean beaker. 5) Prepare a 2.5 mL volumetric pipette for Mg. 6) Get a pipette pump, put it on the volumetric pipette, and pump with Mg solution. 7) Invert to wash the pipette and put waste in slop jar. 8) Prepare 100 mL volumetric flask for H2O. 9) Pipette 25 mL of Mg stock solution into volumetric flask. (USE PIPETTE PUMP) 10) Dilute to the mark with water (comes from the white tap). (If you pass the mark, you must start over) Calculate Magnesium solution CiVi = CfVf (0.01)(25) = x(100) Cf = 0.0025 M I. B. Titration 1) 2) 3) 4) 5) 6)
Put around 25 mL of NH3 buffer in a small beaker. Cover with a watch glass. Pipette 25 mL (use pump) of Mg stock solution into an Erlenmeyer flask. Add 1 dropper of buffer (check for a pH of 10 with pH paper) TF adds EBT indicator. YOU WANT A WINERED COLOR. Record the initial volume on the buret to two decimals.
7) Slowly add the EDTA to the Mg stock solution in the Erlenmeyer flask until it is blue. (DON’T OVER TITRATE) [You can add white paper under it to see the color better] {PURPLE IS VERY CLOSE} 8) Record the final volume on the buret to two decimal places. 9) Repeat I. B. using a fresh 25 mL sample of Mg stock solution. I. C. Repeat I. B. but using the Mg solution you prepared. In calculations, x/y = (CMgVMg)/(CEDTAVEDTA) CMg = 0.01 stock, or 0.0025 your solution VMg = 0.025w ff L Goals; Calculate average x/y, standard deviation of x/y, 95% confidence interval x/y II. Get a pill 1) 2) 3) 4) 5) 6) 7)
Weight pill to 2 decimals. Crush pill with mortar and pestle. Weight out about 0.1 g of crushed powder and record weight. Place in a 250 mL beaker. Add 40 mL of 1.5 M HCl. Stir to dissolve. If solution is not clear, it has to be filtered. a. Get a filter flask, a b funnel, a cover thingy, and filter paper. b. Clamp down. c. Attach to vacuum. d. Turn on vacuum. 8) Transfer filtrate to a 100 volumetric flask. 9) Add H2O to the mark. III. Titrate at least 2 fresh 25 mL samples of Mg pill solution as before. ***May need 23 droppers of buffer to get pH 10*** Data Analysis: What is the mass of Mg in the pill? MMg Pill = (x/y)((CEDTAVEDTA)/VMg Pill)(0.1 L)(24.30g/mol)(mpill/mpowder)[pwoiep
