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Chemistry Forums for Students => Analytical Chemistry Forum => Topic started by: 1800chisaki on May 05, 2020, 11:01:58 AM

Title: How much Na2EDTA.2H2O do i need to weigh to get a 0,01M solution in 250 ml water
Post by: 1800chisaki on May 05, 2020, 11:01:58 AM

i did the following;

n edta = c edta x V H2O
n edta = 0,01 x 250 ml = 2,5 mmol

do i need to multiply n by 2 since edta is a dihydrate? edta is in the H2Y2- form here

further: m edta = n edta x Mr edta
            m edta = 2,5 mmol x 372,24 mg/mmol = 930,6 g

Title: Re: How much Na2EDTA.2H2O do i need to weigh to get a 0,01M solution in 250 ml water
Post by: AWK on May 05, 2020, 11:24:48 AM

Quote

2,5 mmol x 372,24 mg/mmol = 930,6 g

Wrong unit

Title: Re: How much Na2EDTA.2H2O do i need to weigh to get a 0,01M solution in 250 ml water
Post by: 1800chisaki on May 05, 2020, 11:35:14 AM

Quote from: AWK on May 05, 2020, 11:24:48 AM

Quote

2,5 mmol x 372,24 mg/mmol = 930,6 g

Wrong unit

typo, but is my calculation correct? edta being a dihydrate doesnt change anything?

Title: Re: How much Na2EDTA.2H2O do i need to weigh to get a 0,01M solution in 250 ml water
Post by: AWK on May 05, 2020, 11:36:55 AM

After all, you took into account the molar mass of dihydrate.