How much water you have to add to 0.5 kg of Na2So4 in order to make 50% solution?
Answers
Explanation:
Add 0.5kg Na2S04 to 0.5kg of water and you have 1kg of solution of which half is sodium sulfate. So 50%? But hang on, my Handbook of
Chemistry and Physics says it is only soluble to 4.76 grams per 100cc water (cold, more if it's hot). So you will be left with a slurry, not a solution.
Or did the questioner want a 50% solution where 100% is a saturated one? In other words are you aiming for 2.38 grams per 100cc? In which case, the answer is a bit over
20kg. But even so, at what temperature?
Then there's the uncertainty about whether you have anhydrous sodium sulfate
(thenardite) or the decahydrate (mirabilite, Na2S04.10H20) - [which you might well have if you have been delaying the job while you
consult Quora, as the first absorbs water from the air to turn itself into the second.] Or you
might even have the heptahydrate. Whichever, it would throw off your calculations.
So go back to the questioner and ask them to
be more specific.
*Unless its ethanol in water, in which case the answer is yes please, mine's a double.