`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

To demonstrate that the results illustrate the law of constant composition, we will analyze the two experiments step by step.

### Step 1: Analyze the first experiment
In the first experiment, we have:
- Mass of cupric oxide (CuO) = 1.375 g
- Mass of copper (Cu) remaining after reduction = 1.098 g

**Calculate the mass of oxygen (O) in cupric oxide:**
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