Question

2. Using the stock preparation formulation below, (1) calculate the molar concentration of each component in the stock and (2) calculate the molar concentration of each component in the final medium.

Concentration: 200X Use 5 ml stock per liter of medium.

Component g/liter stock

Na2EDTA.2H2O   7.44

FeSO4.7H2O 5.56

Component molar conc in stock molar conc in final medium

Na2EDTA.2H2O

FeSO4.7H2O 5.56

Answer 1

Ans-

Molar concentration = (given mass of solute i.e mass present in solution * 1000)/ (molecular mass of solute*volume of solution (ml) )

Molar concentration of Na2EDTA.2H2O

given mass = 7.44g

molecular mass= 372.24 g/mol

molar concentration= (7.44*1000)/(372.24*1000) = 0.019moles/litres

Molar concentration of FeSO4.7H2O

given mass= 5.56g

Molecular mass = 278g

Molar concentration= (5.56 *1000)/(278*1000) = 0.02moles/litres

Final concentrations- M1V1 = M2V2

M1 = molar concentration in stock solution

V1 = volume of stock solution used

M2= molar concentration in final solution

V2= volume of final solution

molar concentration of Na2EDTA.2H2O-

(0.019*5) = (M2 * 1000)

molar concentration= 9.5 * 10-5 moles/litres

Molar concentration of FeSO4.7H2O

( 0.02*5) = (M2*1000)

molar concentration= 1*10-4moles/litres