vol.determine of au
DESCRIPTION
au determinationTRANSCRIPT
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M297
Hydroquinone, C6H6O2M(C6H6O2) = 110.11 g/mol, z = 2
Hydrochloric acid 0.1 mol/L, Fluka
Cerium sulfate, c(Ce(SO4)2) = 0.01 mol/L
T50/70/90XS205 Balance
C6H6O2 + 2Ce4+ = C6H4O2 + 2Ce
3+ 2H+
Glass beaker, ME-101446Olivetti JobJet 210 PrinterLabX 2.52SP250 Pump, ME-51108016Additional Dosing Unit, ME-51109030
METTLER TOLEDO
Hydroquinone: Evaporate solution, special wasteCerium: Precipitate with NaOH and filtrate,
special waste
Wastedisposal
Preparation and ProceduresHydroquinone, C6H6O2c (1/2 C6H6O2)= 0.05mol/L: 1.5 mL
Sample
Substance
Chemicals
Titrant
Instruments
Results
Chemistry
Accessories
DM140-SCIndication
Factor Determination of Cerium Sulphate vs. Hydroquinone
- Place an empty glass titration beaker on the manual titration stand- 40 mL HCl 0.1 mol/l will be pumped in automatically- 1.5 mL hydroquinone will be dispensed- The sample will be titrated with cerium sulfate 0.01 mol/L using a
DM140-SC electrode
- Weigh 2.753 g hydroquinone in a glass beaker, transfer itwith deionized water into a 1 L measuring flask
- Add approx. 900 mL deionized water- Add 10 mL H2SO4 96%- Fill up to the mark with deionized water
- Pipette 50.0 mL of cerium sulfate 0.1 mol/L (Merck 1.09092.1000)in a 500 mL volumetric flask
- Add approx. 400 mL deionized water- Add 10 mL H2SO4 96% and gentle mix it- Fill up to the mark with deionized water
Theoretical consumption
- 1 mL hydroquinone, c (1/2 0.05 mol/l) corresponds to a consumptionof 5 mL cerium sulfate, c (0.01 mol/L)
Literature
- Application Brochure Gold and Silver DL67/DL70OES/DL77ME-724613
Remarks
R1 = VENDDi*0.05/(VEQ*c)C1 = 1
H[Cerium sulfate] = Mean [R1]
Calculation
Titration Excellence Line: The factor of the cerium sulfate solution will be used for the gold determination ofgold alloys and pure gold. See also applications M298 and M299.
Standard ----
Claudia SchreinerAuthor
Wastedisposal
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Table of measured values
Start time: 22.03.2007Sample Data Note / ID Sample size No. 1/6 Hydroquinone 1.5 mL No. 2/6 Hydroquinone 1.5 mL No. 3/6 Hydroquinone 1.5 mL No. 4/6 Hydroquinone 1.5 mL No. 5/6 Hydroquinone 1.5 mL No. 6/6 Hydroquinone 1.5 mL
Results Note / ID Rx Result Unit No. 1/6 Hydroquinone R1= 0.9828 -- No. 2/6 Hydroquinone R1= 0.9822 -- No. 3/6 Hydroquinone R1= 0.9829 -- No. 4/6 Hydroquinone R1= 0.9832 -- No. 5/6 Hydroquinone R1= 0.9833 -- No. 6/6 Hydroquinone R1= 0.9836 --
Statistics Rx Name n Mean Value Unit s srel[%] R1 Factor 6 0.9830 -- 0.0005 0.05
Titration curve
Results
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Method: M297 Factor cerium sulfate 05.04.2007User: Schreiner
001 Title Typ General titration Compatible with T50/70/90 ID M297 Titel Factor cerium sulfate Author Mettler Toledo Date / Time 05.04.2007 Modified at 05.04.2007 Protect No SOP None LabX SOP002 Sample Number of IDs 1 ID 1 Hydroquinone Entry Type Fixed volume Volume [mL] 1.5 Density [g/mL] 1.0 Correction factor 1.0 Temperature [C] 25.0 Entry Arbitrary003 Titration stand Typ Manual stand Titration stand Manual stand 1004 Pump Auxiliary reagent HCl 0.1 mol/L Volume [mL] 40 Condition No005 Dispense
Titrant 1/2 Hydroquinone Concentration [mol/L] 0.05 Volume [mL] 1.5 Dosing rate [mL/min] 60.0 Condition No006 Stir
Speed [%] 35 Duration [s] 10 Condition No007 Titration (EQP)Titrant Titrant Cerium sulfate Concentration [mol/L] 0.01Sensor Typ mV Sensor DM140-SC Unit mVTemperature aquisition Temperature aquisition NoStir Speed [%] 35Predispense Mode Volume Volume [mL] 5 Wait time [s] 5Control Control User Titrant addition Dynamic dE (set value) 8 dV (min) 0.005 dV (max) 0.2 Mode Equlibrium controlled dE 0.5 dt [s] 2 t(min) [s] 3 t(max) [s] 30Evaluation and Recognition Procedure Standard Threshold 500 Tendency Positive Ranges 0 Add. EQP criteria NoTermination At Vmax [mL] 10 At potential No At Slope No After numbered of recognized EQPs Yes Number of EQPs 1 Combined termination criteria No
MethodAccompanying stating
Accompanying stating NoCondition
Condition No008 Calculation
Result Factor Result Unit ---- Formula R1=VENDDi*0.05/(VEQ*c) Constant C= 1 M None z None Decimal places 5 Result limits No Record statistics Yes Extra statistical functions No Condition No009 End of sample
010 Auxiliary Value Name Cerium sulfate Formula H= Mean[R1] Limits No Condition No
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