\(1.08 \mathrm{~g}\) of copper wire was allowed to react with nitric acid. The resulting solution was dried and ignited when \(1.35 \mathrm{~g}\) of copper oxide was obtained. In another experiment \(2.30 \mathrm{~g}\) of copper oxide was heated in presence of hydrogen yielding \(1.84 \mathrm{~g}\) of copper. Show that the above data are in accordance with law of constant proportion.

Chemical reactions are fundamental processes by which substances interact to form new products. Each reaction involves a rearrangement of atoms and a change in the way they are bonded together. In the context of our exercise, copper reacts with nitric acid to form copper oxide, showcasing how elements combine to create compounds with different properties.

To further understand chemical reactions, it's key to note that they are governed by laws. An important law in this context is the Law of Conservation of Mass, which states that mass is neither created nor destroyed in a closed system. Moreover, reactions follow stoichiometry, an area of chemistry that quantifies the relationship between reactants and products.

Stoichiometry refers to the calculation of reactants and products in chemical reactions. It is a vital concept in chemistry, for it allows us to predict the amounts of substances consumed and produced in any given reaction. In our exercise, stoichiometry is used to calculate the mass of oxygen that reacts with a known mass of copper to form copper oxide.

To perform stoichiometric calculations, it is necessary to know the balanced equation for the chemical reaction and to apply the Law of Constant Proportion. This law states that no matter the size of the sample, a chemical compound always contains the same elements in the same proportion by mass. The calculation steps in the provided solution align with these stoichiometric principles.

Experimental verification is key in confirming the validity of chemical laws. The Law of Constant Proportion can be confirmed through experiments that measure the mass of reactants and products, as conducted in the provided exercise. By analyzing two separate experiments of copper and oxygen combining to form copper oxide and verifying that the ratio of the masses of copper to oxygen remains constant, we support the law's statement.

This consistency of proportion is expected to hold true, regardless of the method or scale of the experiment. It reflects the chemical compound's definitive composition. Hence, careful measurement and calculation are crucial to verify that even across separate experiments, a compound's makeup complies with this law.

Percentage composition is a measure of the relative amount of each element within a compound. It is calculated by dividing the mass of each element by the total mass of the compound and then multiplying by 100 to get a percentage. This concept is fundamental when assessing a compound's makeup and is inherently related to the Law of Constant Proportion.

In our exercise, the percentage composition would involve finding the percentage by mass of copper and oxygen in copper oxide. From the calculated masses in both experiments, you can confirm that the percentage remains consistent, further affirming the law. Percentage composition not only provides insight into a compound's identity but also offers a basis for stoichiometric calculations in chemical reactions.