Moderate
80 kg of Na2SO4 (molecular weight = 142) is present in 330 kg of an aqueous solution. The solution is cooled such that. 80 kg of Na2SO4 .10H2O crystals separate out. The weight fraction of Na2SO4 in the remaining solution is_________________?
Correct answer: B. 0.18
- A. 0.00
- B. 0.18
- C. 0.24
- D. 1.00
Explanation
The crystals contain 142/(142 + 180) = 0.441 of Na2SO4, so they remove 35.3 kg salt and 44.7 kg water. The remaining solution weighs 250 kg and contains 44.7 kg Na2SO4, giving a mass fraction of about 0.18.
Written and checked by Zahid Hussain, MS Computer ScienceLast updated
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