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ข้อคิดเห็นที่
1: Example : Preparation of 1000 mL 1.0 N Hydrogen peroxide ( H2O2 ) from 30 % H2O2 Molar Weight of Hydrogen peroxide = 34.0147 g / Mole = 34014.7 mg / Mole ( Normal ) Equivalent Weight of Hydrogen peroxide = 0.5 x ( 34.0147 g ) = 0.5 x 34014.7 mg = 17007.35 mg Amount of 30 % H2O2 needed = 17007.35 mg x ( 100 % / 30 % ) = 56690.1 mg ( + required amount of pure water to make 1000 mL ) There is no need to weigh exactly 56690.1 mg of 30 % H2O2 ; The 1.0 N H2O2 Solution will gradually decompose and the final concentration will be less than 1.0 N It is better to weigh 57 g of 30 % H2O2 and mix with 950 mL of cold pure water . Or Weigh 57 g of 30 % H2O2 into a 1000 mL Volumetric Flask and add cold pure water to get 1000 mL of solution . โดย: นักเคมี [28 ม.ค. 2554 01:31] |