Question

навеску смеси сульфатов калия и натрия массой 158 грамм растворили в воде и обработали избытком хлорида бария . в результате образовался осадок массой 233 грамм. вычислите массовые доли сульфатов в исходной смеси

Answer 1

K₂SO₄+Na₂SO₄+2BaCl₂=2KCl+2NaCl+2BaSO₄
K₂SO₄+BaCl₂=2KCl+BaSO₄
174                            233
x                                 a=233x/174
Na₂SO₄+BaCl₂=2NaCl+BaSO₄
142                                 233
y                                      b=233y/142
233x/174+233y/142=233
x+y=158
x=K₂SO₄=87 г., y=Na₂SO₄=71 г.
ω(K₂SO₄)=87/158,   ω(Na₂SO₄)=71/158

Answer 2

Calculation of Mass Fractions of Sulfates in the Mixture

To calculate the mass fractions of sulfates in the initial mixture, we need to use the information provided. According to the question, a mixture of potassium sulfate (K2SO4) and sodium sulfate (Na2SO4) with a total mass of 158 grams was dissolved in water. This solution was then treated with an excess of barium chloride (BaCl2), resulting in the formation of a precipitate with a mass of 233 grams.

To determine the mass fractions of sulfates in the mixture, we can use the stoichiometry of the reaction between sulfates and barium chloride. The balanced equation for the reaction is as follows:

BaCl2 + Na2SO4 → BaSO4 + 2NaCl

From the equation, we can see that one mole of barium chloride reacts with one mole of sodium sulfate to form one mole of barium sulfate. Therefore, the molar ratio between barium sulfate and sodium sulfate is 1:1.

Since the mass of the precipitate formed is 233 grams, we can assume that all of it is barium sulfate. This means that the mass of sodium sulfate in the mixture is also 233 grams.

To calculate the mass fraction of sodium sulfate, we divide the mass of sodium sulfate by the total mass of the mixture:

Mass fraction of sodium sulfate = (mass of sodium sulfate) / (total mass of mixture)

Mass fraction of sodium sulfate = 233 grams / 158 grams

Calculating this value gives us the mass fraction of sodium sulfate in the mixture.

Now, let's calculate the mass fraction of potassium sulfate. Since the total mass of the mixture is 158 grams and the mass of sodium sulfate is 233 grams, we can subtract the mass of sodium sulfate from the total mass to find the mass of potassium sulfate:

Mass of potassium sulfate = (total mass of mixture) - (mass of sodium sulfate)

Mass of potassium sulfate = 158 grams - 233 grams

Calculating this value gives us the mass of potassium sulfate in the mixture.

Finally, we can calculate the mass fraction of potassium sulfate by dividing the mass of potassium sulfate by the total mass of the mixture:

Mass fraction of potassium sulfate = (mass of potassium sulfate) / (total mass of mixture)

Mass fraction of potassium sulfate = (calculated mass of potassium sulfate) / 158 grams

Calculating this value gives us the mass fraction of potassium sulfate in the mixture.

Please note that the exact values for the mass fractions of sodium sulfate and potassium sulfate cannot be determined without additional information, such as the molar masses of the compounds involved. However, the above calculations provide a general approach to solving the problem.