Question

In an experiment, 6.8 g of Cu was obtained by the reduction of 8.2 g CuO with hydrogen. In another experiment, 3.4 g of copper was oxidised and 4.1 g of copper oxide was obtained. Prove that these results illustrate the law of constant proportions.

Answer 1

Answer:

In the first experiment:-

Weight of copper oxide, (CuO)=1.288g

Weight of copper =1.03g

Weight of oxygen = Wt. of copper oxide − Wt. of copper =1.288−1.03=0.258g

∴

Wt. of oxygen

Wt. of copper

=

0.258

1.03

≈

1

4

In the second expriment:-

Weight of copper oxide (CuO)=3.672g

Weight of copper =2.938g

Weight of oxygen = Wt. of copper oxide − Wt. of copper =3.672−2.938=0.734g

∴

Wt. of oxygen

Wt. of copper

=

0.734

2.938

≈

1

4

The proportion of elements of copper and oxygen in the reactions is same.

Hence law of constant proportion is proved.

Answer 2

Answer:

Weight of copper oxide, (CuO)=1.288g

Weight of copper =1.03g

Weight of oxygen = Wt. of copper oxide − Wt. of copper =1.288−1.03=0.258g

∴

Wt. of oxygen

Wt. of copper

=

0.258

1.03

≈

1

4

In the second expriment:-

Weight of copper oxide (CuO)=3.672g

Weight of copper =2.938g

Weight of oxygen = Wt. of copper oxide − Wt. of copper =3.672−2.938=0.734g

∴

Wt. of oxygen

Wt. of copper

=

0.734

2.938

≈

1

4

The proportion of elements of copper and oxygen in the reactions is same.

Hence law of constant proportion is proved.

Explanation: