Final answer:
A balanced chemical equation for the reaction of nitrogen gas with hydrogen gas to produce ammonia shows the stoichiometric relationships between reactants and products, conserving mass.
Step-by-step explanation:
When the chemist reacts three moles of N₂ with six moles of H₂, the balanced chemical equation would reflect the stoichiometric relationship between the reactants. The balanced equation for this reaction is N₂ + 3H₂ → 2NH₃. This equation indicates that one mole of nitrogen gas reacts with three moles of hydrogen gas to produce two moles of ammonia. It showcases the conservation of mass, where the total mass of the reactants equals the total mass of the products.
The mass number, as seen in Chapter 2, represents the total number of protons and neutrons in an atom's nucleus. Chapter 6 discusses the concept of chemical composition and the importance of understanding the proportions of elements within compounds and their relevance in chemical reactions.