lab5report - Total HCl Used (mL) 25.75 39.65 19.40...

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Carla Paulo Exercise 5 Kjeldahl Ammonium Analysis Purpose: To determine the amount of ammonium in an unknown compound using the Kjeldahl analysis method. Unknown #: Unknown 5F Important Equations: NH 3 + H 3 BO 3 NH 4 + + H 2 B0 3 - HCl + H 2 BO 3 - H 3 BO 3 + Cl - Safety Factors: Wear goggles and gloves. Handle solutions with care. Wear thermal gloves to handle hot glassware. Remember to add boiling stones. Have TA set up. Raw Data: Preparation of Unknown: Trial 1 Trial 2 Trial 3 Mass Vial Initial (g) 24.1068 23.8182 23.5527 Mass Vial Final (g) 23.8182 23.5527 23.4250 Total Mass Unknown (g) 0.2886 0.2655 0.1277 Titration of Unknown Trial 1 Trial 2 Trial 3 Volume of HCl Initial (mL) 0.30 1.35 1.40 Volume of HCl Final (mL) 26.05 41.00 20.80
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Unformatted text preview: Total HCl Used (mL) 25.75 39.65 19.40 Treatment of Results: % NH 4 + in the Unknown: Trial 1: 0.02575L HCl x(0.1005mol HCl/1L HCl)x (1mol H 2 BO 3-/1mol HCl)x (1molNH 4 + /1mol H 2 BO 3-)x (18.04g/1mol NH 4 + )= 0.0467g NH 4 + (0.0467g NH 4 + /0.2886g unknown) x 100= 16.18% Trial %NH 4 + 1 16.18 2 27.08 3 27.56 Average: 23.61% Standard deviation: 5 Q-test: Trial 1 deviates from the average the most Q(exp)= (27.08 16.18)/(27.56-16.18)= 0.955 Since the Q(crit) is 0.94 and Q(exp) is more than Q(crit), trial 2 does not have to be retained. Conclusion: The average %NH 4 + in the unknown sample 5F was 27.32 1%...
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This note was uploaded on 12/07/2011 for the course CHEM 328 taught by Professor Soriaga during the Spring '10 term at Texas A&M.

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lab5report - Total HCl Used (mL) 25.75 39.65 19.40...

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