Question

please answer the question fast

Answer 1

1st experiment ,
2Cu + O2 →2CuO
2mole of Cu form 2mole of CuO
127g of Cu form 159 g of CuO
1 g of Cu form 159/127 g of CuO =1.25g of CuO
now,


1.288g of CuO obtained with 1.03 g Cu
1.03 of Cu form 1.288 g of CuO
1g of Cu form 1.288/1.03 g of CuO = 1.25g

now,
2nd experiment ,

2.938 g of Cu form 3.672 g of CuO
1g of Cu form 3.672/2.938 g of CuO = 1.25 g

here you see in both experiments Cu react with oxygen form same quantity of CuO .

so, here Law of definite proportion and also law of conservation of mass satisfied .

but we know , all chemical reaction satisfied law of conservation of mass
so, here we give priority of Law of definite proportion .