What does Gay-Lussac's law of combining volumes state about reactive gases?

Gay-Lussac's law of combining volumes states that when gases react together at constant temperature and pressure, they do so in volumes that are in simple whole number ratios. This means that if two gases react, the volumes of the reacting gases and the volumes of the products can be expressed as ratios of small whole numbers. For example, if one volume of gas A combines with two volumes of gas B to produce two volumes of gas C, the ratio of their volumes is 1:2:2. This law highlights the quantitative relationship between the volumes of gaseous reactants and products, emphasizing the simplicity of these ratios in gas reactions.

Understanding this law is crucial in stoichiometry and gas reactions, as it lays the foundation for predictions and calculations involving gaseous substances. It underscores the idea that reactions involving gases can be understood and modeled through their volumes, distinguishing them from reactions that produce liquids or solids where volume might not be conserved in the same straightforward manner.