The balanced chemical equation for the decomposition of sodium nitride is 2Na₃N → 6Na + N₂. This equation accurately represents how sodium nitride breaks down into its elemental components: solid sodium and gaseous diatomic nitrogen.
Understanding Sodium Nitride (Na₃N)
Sodium nitride is an inorganic compound formed from sodium (Na) and nitrogen (N).
- Sodium (Na) is an alkali metal, typically forming a +1 ion (Na⁺).
- Nitrogen (N), when forming nitrides, typically forms a -3 ion (N³⁻).
- To achieve electrical neutrality, three sodium ions are required for every one nitride ion, leading to the chemical formula Na₃N. This formula is inherently balanced in terms of electrical charge within the compound itself.
The Decomposition of Sodium Nitride
When sodium nitride decomposes, it breaks down into its constituent elements: metallic sodium (Na) and diatomic nitrogen gas (N₂). The initial, unbalanced chemical equation for this process is:
Na₃N → Na + N₂
Step-by-Step Balancing Process
Balancing a chemical equation ensures adherence to the Law of Conservation of Mass, stating that matter cannot be created or destroyed in a chemical reaction. This means the number of atoms for each element must be identical on both the reactant and product sides of the equation.
Let's walk through the balancing steps, reflecting the process commonly demonstrated in educational resources such as the referenced video titled "How to Balance Na3N = Na + N2 (Sodium nitride Decomposing)":
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Identify Initial Atom Counts:
- Reactant Side (Na₃N):
- Sodium (Na): 3 atoms
- Nitrogen (N): 1 atom
- Product Side (Na + N₂):
- Sodium (Na): 1 atom (As noted in the reference, "Product side we have one sodium.")
- Nitrogen (N): 2 atoms (As noted in the reference, "...and two nitrogen atoms.")
- Reactant Side (Na₃N):
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Balance Nitrogen Atoms:
- Given there is 1 nitrogen atom on the reactant side (in Na₃N) and 2 on the product side (in N₂), we need to increase the nitrogen on the reactant side. A common strategy, as hinted in the reference ("I think what i'll do is i'll try to balance the nitrogens."), is to start with elements that appear in fewer compounds.
- To balance nitrogen, place a coefficient of 2 in front of Na₃N:
- 2Na₃N → Na + N₂
- Now, on the reactant side, we have 2 × 3 = 6 Na atoms and 2 × 1 = 2 N atoms.
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Balance Sodium Atoms:
- Currently, we have 6 sodium atoms on the reactant side (from 2Na₃N) but only 1 sodium atom on the product side (Na).
- To balance the sodium atoms, place a coefficient of 6 in front of the Na on the product side:
- 2Na₃N → 6Na + N₂
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Verify Final Atom Counts:
- Let's check the number of atoms for each element on both sides of the balanced equation:
| Element | Reactant Side (2Na₃N) | Product Side (6Na + N₂) |
|---|---|---|
| Sodium (Na) | 2 × 3 = 6 | 6 × 1 = 6 |
| Nitrogen (N) | 2 × 1 = 2 | 1 × 2 = 2 |
* As confirmed in the table, the number of atoms for both sodium and nitrogen are equal on both sides, verifying that the equation is now correctly balanced.Importance of Balancing Chemical Equations
Balancing chemical equations is a fundamental practice in chemistry. It is essential because it visually represents the Law of Conservation of Mass, a core principle stating that matter cannot be created or destroyed during a chemical reaction. A balanced equation ensures that the total mass of the reactants precisely equals the total mass of the products. Furthermore, it provides the correct stoichiometric ratios, which are vital for predicting reaction yields, calculating reactant and product quantities, and understanding the quantitative relationships within chemical processes.
