Final answer:
Ammonium nitrate (NH4NO3) decomposes into nitrogen gas (N2), oxygen gas (O2), and water vapor (H2O) when heated, demonstrating the law of conservation of mass.
Step-by-step explanation:
The decomposition of ammonium nitrate (NH4NO3) can be represented by the chemical equation:
2NH4NO3 (s) → 2N2 (g) + O2 (g) + 4H2O(g)
This reaction explains the thermal decomposition of ammonium nitrate where ammonium ion (NH4+) and nitrate ion (NO3-) react to produce nitrogen gas (N2), water vapor (H2O), and oxygen gas (O2). The ionic bond between NH4+ and NO3- in ammonium nitrate is broken by heat. An important aspect of this reaction is that it demonstrates the law of conservation of mass, meaning the total mass of the reactants equals the total mass of the products, adhering to the principle that matter cannot be created or destroyed in a chemical reaction. All substances are represented with their correct coefficient to balance the equation in terms of the number of atoms for each element.
When ammonium nitrate is heated above its melting point (170°C), it decomposes completely, indicating the reaction goes to completion without any residual ammonium nitrate. This is crucial in applications such as an oxygen source in chemical reactions or in the manufacturing of fertilizers.
The enthalpy change, ΔH, and the other thermodynamic properties can be calculated knowing the substances involved and their respective standard enthalpies of formation.