`1.375 g` of cupric oxide was reduced by heating in a current of hydrogen and the weight of copper that remained was `1.098 g` In another experiment, `1.179 g` of copper was dissolved in nitric acid and the resulting copper nitrate converted into cupric oxide by ignition. The weight of cupric oxide formed was `1.476 g`. Show that these result illustrate the law of constant composition.

Explanation

In the first experiment:
`"Mass of CuO "= 1.375g`
`"Mass of Cu" = 1.098g`
`"Mass of Oxygen" = 1.375 -1.098 = 0.277g`
`"Ratio of Cu:O "= 1.098 : 0.277 = 3.96 : 1`
In the second experiment:
`"Mass of CuO "= 1.476g`
`"Mass of Cu" = 1.178g`
`"Mass of oxygen" = 1.476 - 1.178 = 0.298 g`
`"Ratio of Cu:O" = 1.178 : 0.298 = 3.96 : 1`
In both experiment we get ratio of Cu to oxygen as `3.96 : 1` which shows that law of definite proportions is true.