Question

QUESTION 5                  8 MARKS
a) How many grams of BaCl2.2H2O (MW = 244.27 g/mol) you need to prepare 250
mL of 0.15 M chloride ion solution?
2 marks
b) It was established that this reagent was contaminated by CaCl2 (MW = 181.82
g). The content of calcium in the solid sample was found to be 4750 ppm (w/w).
What was the percentage decrease in the molar Barium ion concentration
caused by this contamination?
6 marks

hi chemists I recieved this question after my practical today to work on at home can someone please help me

Answer 1

How many grams of BaCl2.2H2O (MW = 244.27 g/mol) you need to prepare 250
mL of 0.15 M chloride ion solution?

M = n solute / V solution L

M = (mass / molar mass) / V solution L
MV = mass / molar mass
MV(molar) = mass
plugging values

for the mass.
MV(molar) = mass
(0.15 M)(0.25 L)(244.27 g/mol) = mass
9.16 g = mass ------Answer)

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