Question

how much copper is present in 100g of CuSO4.

Answer 1

160 g of CuSO4 gives 64 g of Cu
therefore, 1 g of cuso4 will give 64/160 g of cu
and, 100 g will give 64/160*100 = 4 g

Hope this helps u.

Answer 2

Finding copper is present in 100g of CuSO4 -

We know that 
Mass of CuSO4 = 160g
and mass of Cu in CuSO4 = 64g

∴1 g of Cu in CuSO4 = 64/160 g 
⇒100 g of Cu in CuSO4 = 64/160 *100 g
                                        =40 g

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Best of luck ;)
ROYALJATT