Question

1.375 g of cupric oxide, on reduction in hydrogen gas gives 1.098 g of copper.
1.179 g of copper of copper is produced by 1.476 grams of copper oxide.

Find out the mass % of copper in both the cases.

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Answer 1

According to the law of constant proportion, A chemical compound always contains the same elements combined together in the same proportion by the mass.

1.375 g of cupric oxide contains 1.098g of copper.

1.375 - 1.098 = 0.277g (oxygen)

The ratio of copper to oxygen is

0.277

1.098

= 3.9 : 1

= 4:1