1000g海水中最多可提取多少氯化鈉(NaCl)

1000g海水中最多可提取多少氯化鈉?
A.100g
B. 35g
C. 24g
D. 3.5g


答案是： B. 35g

世界海水的含氯化鈉約 3.5%。
（參考： http://zh.wikipedia.org/wiki/%E6%B5%B7%E6%B0%B4）
1000 g 海水含氯化鈉的重量 ≈ (1000 g)x 3.5% = 35 g

The conc of NaCl in sea water is about 0.5 molar .
1Kg of water ia 1000g , which at density of 1g/ml .
At a molarity of o.5 mol per l , 1kg of sea water will contain 0.5 mol of NaCl which has mas of of 58.5g , half mol is about 30 g .
The ans is about 30 g .



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2011-05-03 17:26:19 補充：
Sorry in the second line : at density of 1 g/ml. will follow by .....is a volume of 1litre .