An excess of barium chloride solution was added to a solution of potassium carbonate with a mass fraction of 6%. As a result of the reaction, a precipitate weighing 9.85 g was formed. Determine the mass of the initial potassium carbonate solution.
The interaction of barium chloride with potassium carbonate results in the formation of an insoluble precipitate of barium carbonate. The course of this reaction is described by the following equation:
BaCl2 + K2CO3 = BaCO3 + 2KCl;
Let’s calculate the chemical amount of the obtained barium carbonate. To do this, we divide its weight by its molar mass, equal to the sum of the molar weights of the atoms included in the molecule.
M BaCO3 = 137 + 12 + 16 x 3 = 197 grams / mol;
N BaCO3 = 9.85 / 197 = 0.05 mol;
To obtain this amount of barium carbonate, it is necessary to take the same amount of potassium carbonate.
Let’s define its mass:
For this purpose, we multiply the weight of the precipitate by its molar mass, which is equal to the sum of the molar weights of the atoms included in the molecule.
M К2СO3 = 39 x 2 + 12 + 16 x 3 = 138 grams / mol;
m K2CO3 = 138 x 0.05 = 6.9 grams;
The mass of the initial solution of potassium carbonate will be: 6.9 / 0.06 = 115 grams;
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