Question

copper oxide was prepared by two different methods. in one case 1.75g of metal give 2.19g of oxide .in second case 1.14g of metal gave 1.43g of oxide show that the given data illustrate law of constant proportion

Answer 1

Answer:

case I, mass of copper = 1.75 g

Mass of copper oxide = 2.19 g

% of copper in the oxide =Mass of copperMass of copper oxide×100=Mass of copperMass of copper oxide×100

=1.752.19×100=79.9%=1.752.19×100=79.9%

∴%∴% of oxygen =100−79.9=20.1%=100-79.9=20.1%

In case II, mass of copper = 1.14 g

Mass of copper oxide = 1.43 g

% of copper in the oxide =1.141.43×100=79.7%=1.141.43×100=79.7%

% of oxygen = 100 - 79.7 = 20.3 %.

Thus, copper oxide prepared by any of the given methods contain copper and oxygen in the same proportion by mass (with the experimental error). Hence, it proves the law of constant proportions.