Question

Calculate the mass of copper sulphate and mass of water required to make 200g of 25% solution of copper sulphate.

Answer 1

Answer : 175 g of water should be added to make 8%/w solution of cuso4

Mol. wt of cuso4.5h20 is (63+32+48+9) =249

Means 249 g of cuso4 contain 90 g of h20

So 1 gram of cuso4 contain( 90÷249)

So 25 g of cuso4 will have (90÷249)×25 = 9.0 grm of water (approx) and 16 g of cuso4

For making 8% by wt ( density of water 1g/ml)

8÷100= 16÷(25+W) ,

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where desolved substance is cuso4.5h20 which is 25 g in W g of h20

W= 175 gram