英語翻譯
4.2 Production of Reagent 1,1l:
1.Measure 1l H2SO4 75% in a 1l measuring cylinder and fill it in a 1l flask black.
2.Close the flask and label the flask.
3.Check if the flask is not leaking.
4.Repeat the steps 1.- 3.for flask 2.-4.
4.3 Production of Reagent 2,250ml:
1.Prepare under cooling a 20% H2SO4 after densitiy (r = 1,139 g/cm3 at 20°C) using approx.220 ml ultrapure water and approx.40 ml H2SO4 80%.For a bigger batch use according multiple amounts.
2.Measure 250 ml (± 1.5 ml) H2SO4 20% with a measuring cylinder.
3.Put a weighing dish on a balance (for analysis) and tare.
4.Weigh in 1.265 g Ag2SO4 with the help of an applicator.
5.Fill up with 20% H2SO4 to approx.200 ml.
6.Stirr until it is completly desolved.
7.Weigh in 0.809 g K2Cr2O7 with the help of an applicator in a weighing dish.
8.In an extractor hood transfer the weighed in amount of K2Cr2O7 with the rest of 20% H2SO4 completely into the beaker.
9.Stirr at 40°C (heating plate) until it is completely desolved.
10.Transfer the warm reagent in a 250 ml flask black.
11.Close the flask and label the flask
12.Check if the flask is not leaking.
4.4 Production of Reagent 3,50g:
1.Put a 100 ml plastic flask on a balance (for analysis) and tare.
2.Weigh in 50 g saccharose with the help of an applicator and a powder funnel.
3.Close the flask and label the flask.