Question dealing with gravimetric analysis lab.

Question

Approximately how many mL of 5% BaCl₂2H₂O solution would be required to precipitate all the sulfate if we assume that your samples are pure sodium sulfate? Assume that the density of the barium chloride solution is 1.00 g/mL. The mass of the sodium sulfate is 0.3559 grams

If the samples were pure potassium sulfate would you require a smaller or larger volume of barium chloride solution than the amount calculated in the previous question?

Answer 1

Start with how much stuff and end with how much stuff:

.3559 g Na₂SO₄ (mole/g Na₂SO₄)(1 BaCl₂/1Na₂SO₄)(g / mole BaCl₂•2H₂)(100ml/5g BaCl₂•2H₂O)

That gives you ml of solution. You can calculate or find the molar masses of the two compounds. Multiplying by moles/g is dividing by the molar mass.

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