The determination of sulfate in natural waters

Question

The determination of sulfate in natural waters is achieved by a variety of methods, for example ion chromatography, gravimetry, turbidimetry.

To prepare 1 L of stock standard solution of 1000 mg/L sulfate (1000 mg SO₄^2-/L) using sodium sulfate (anhydrous) one would:

Select one:

a. Dissolve 1.3212g sodium sulfate and make up to 1.000 L final volume.

b. Dissolve 1.2394 g sodium sulfate and make up to 1.000 L final volume.

c. Dissolve 1000 mg sodium sulfate and make up to 1.000 L final volume.

d. Dissolve 4.4304g sodium sulfate and make up to 1.000 L final volume.

e. Dissolve 1.4787 g sodium sulfate and make up to 1.000 L final volume.

Answer 1

Hello again Akshay W.,

Again, I don't see evidence that you have thought about this problem. So how would you convert 1 g of SO4 (what you need) into the same equivalent of Na2SO4 (what you have and must weigh out)? Find some molar masses (add the atomic masses!) for your part and for the whole, and perform the appropriate division!

-- Cheers, -- Mr. d.