Question

In an experiment, 4.90g of copper oxide was obtain

Answer 1

Law of Constant Proportion is to Be Followed

Explanation:

The law of constant proportion ALSO CALLED as law of definite proportion.  

• Which states that in any compound, elements are always present in definite proportions by mass.  

The reaction between copper and oxygen to get Copper Oxide is as follows

$2Cu + O_2 \ -> 2CuO$

As per the data,  

4.90 g of copper oxide was obtained from 3.92 g of copper. So, the percentage of copper in 4.90g of CuO will be

= $\frac {mass\ of\ Copper}{mass\ of\ CuO} \times 100$

= $\frac {3.92}{4.9} \times 100$

= 80%

As per the data for II experiment,  

3.64g of copper is obtained from 4.55g of CuO.  

So, percentage of copper in this sample of copper oxide will be

= $\frac {Mass\ of\ Copper}{Mass\ of\ CuO} \times 100$

= $\frac{3.64}{4.55} \times 100$

= 80 %

Hence, we got percentage of copper in both CuO Samples which was SAME, which means they both combine in FIXED RATIO by MASS to make CuO.

Hence, Law of Constant Proportions Satisfied!

Answer 2

REFER TO THE ATTACHMENT...