Kodak ECN-0002/1 manual Example Potentiometric Calculations

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Example Potentiometric Calculations:

Titration		mL 0.1 N Na2S2O3 Titrant
Blank A	=	40.50
Sample A	=	21.85
Blank B	=	40.55
Sample B	=	19.80

Hypo Index (HI) or Total Reductants:

(40.50 – 21.85)(0.0989)

HI (1), mL =

0.1000

= 18.4 mL 0.1000 N I2

Thiosulfate (S2O3=):

g/L S2O3= =

(40.55 – 19.80)(0.0989)(112.13)(1000)

(2.0)(1000)

= 57.5 g/L

Sodium Sulfite (Na2SO3):

[(40.50 – 21.85)(2.0) – (40.55 – 19.80)](0.0989)(63.02)(1000)

g/L Na2SO3 =

(2.0)(1000)

= 51.4 g/L

Processing KODAK Motion Picture Films, Module 3, Analytical Procedures • H24.03

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Contents Precision and Bias IntroductionRepeatability ReproducibilityBias Potentiometric Titration StatisticsThiosulfate SulfiteHypo Index RecoveryThiosulfate S2O3= Visual Titration StatisticsHypo Index 1 mL 73.3% Procedure ApparatusReagents Sulfite Thiosulfate DeterminationFor Visual Titration Hypo Index HI or Total Reductants Thiosulfate HypoCalculations Thiosulfate S2O3=Sodium Sulfite Na2SO3 Example Potentiometric Calculations ML I2N I2eq. wt. S2O3=1000 S2O3= = ML Sample size1000