Chemical equation
N₂ + H₂ → NH₃ Balanced Equation
The N2 H2 NH3 balanced equation is N₂ + 3H₂ → 2NH₃. Nitrogen gas reacts with hydrogen gas to form ammonia, and the smallest whole-number coefficient ratio is 1 : 3 : 2.
Quick answer
Start with and balance it by placing 3 before H₂ and 2 before NH₃.
| Coefficients | 1 : 3 : 2 |
|---|---|
| Reaction type | Synthesis / Combination |
| Mole ratio | 1 : 3 : 2 |
Balanced Equation for N₂ + H₂ → NH₃
The coefficient table shows why the balanced ratio is 1 : 3 : 2.
Balanced equation
| Compound | Coefficient |
|---|---|
| N₂ | 1 |
| H₂ | 3 |
| NH₃ | 2 |
Read the balanced equation as: 1 molecule or mole of N₂ reacts with 3 molecules or moles of H₂ to produce 2 molecules or moles of NH₃. In a classroom answer, this is often written as N2 + 3H2 = 2NH3.
How to Balance N₂ + H₂ → NH₃
Balance the atoms by changing coefficients only. Do not change subscripts such as the 2 in N₂ or the 3 in NH₃.
Step 1
Start with the equation
N₂ + H₂ → NH₃
Step 2
Balance nitrogen
N₂ has 2 nitrogen atoms, so put 2 before NH₃: N₂ + H₂ → 2NH₃.
Step 3
Balance hydrogen
2NH₃ contains 6 hydrogen atoms, so put 3 before H₂: N₂ + 3H₂ → 2NH₃.
Step 4
Check the atom count
Reactants and products now both contain 2 N atoms and 6 H atoms.
After nitrogen and hydrogen are both balanced, the final N2 + H2 balanced equation is N₂ + 3H₂ → 2NH₃.
Atom Conservation Check
A balanced equation must have the same number of each type of atom before and after the arrow.
| Element | Before | After |
|---|---|---|
| Nitrogen | 2 | 2 |
| Hydrogen | 6 | 6 |
The reactant side has 2 nitrogen atoms and 6 hydrogen atoms. The product side has the same counts in 2NH₃, so the equation is balanced.
N₂ + H₂ → NH₃ Mole Ratio
Balanced coefficients become the mole ratio used in stoichiometry.
Mole ratio
N₂ : H₂ : NH₃ = 1 : 3 : 2
One mole of N₂ reacts with three moles of H₂ to produce two moles of NH₃. A quick stoichiometry example is therefore:
1 mol N₂ + 3 mol H₂ → 2 mol NH₃
2 mol N₂ needs 6 mol H₂ and forms 4 mol NH₃.
Calculate grams, moles, or product amounts for this reaction in the stoichiometry calculator.
What Type of Reaction Is N₂ + H₂ → NH₃?
This is a synthesis, or combination, reaction because two reactants combine to form a single compound.
| Reaction type | Synthesis / combination |
|---|---|
| Pattern | A + B → AB |
| Product | Ammonia (NH₃) |
In the unbalanced formula, N₂ and H₂ are separate reactants. In the balanced equation, they combine into NH₃, so the reaction follows the pattern A + B → AB.
This reaction is the basis of industrial ammonia synthesis. For most homework and calculator uses, the key pieces are the balanced equation, atom count, and mole ratio.
Common Mistakes When Balancing N₂ + H₂ → NH₃
Most wrong answers come from changing formulas instead of using coefficients.
Do not change subscripts
N₂, H₂, and NH₃ are fixed formulas. Changing NH₃ to NH₂ or NH₆ would describe a different substance.
Do not leave hydrogen unbalanced
N₂ + H₂ → 2NH₃ balances nitrogen, but it leaves only 2 H atoms before the arrow and 6 H atoms after it.
Use the smallest whole numbers
2N₂ + 6H₂ → 4NH₃ is balanced, but it reduces to the simpler coefficient ratio 1 : 3 : 2.
Reactants and Product
Identify each formula before using the equation in a mole-ratio, limiting-reactant, or theoretical-yield calculation.
| Side | Formula | Name |
|---|---|---|
| Reactant | Nitrogen | |
| Reactant | Hydrogen | |
| Product | Ammonia |
Use This Equation in Chemistry Calculators
Once the equation is balanced, you can use it to work with specific amounts of N₂, H₂, or NH₃.
If N₂ and H₂ are not supplied in a 1 : 3 mole ratio, one reactant will limit the amount of NH₃ that can form. You can also calculate the maximum theoretical yield of ammonia from a known reactant.
- Use in Stoichiometry CalculatorConvert between N₂, H₂, and NH₃ using the 1 : 3 : 2 mole ratio.
- Find Limiting ReactantCheck whether nitrogen or hydrogen runs out first for your amounts.
- Calculate Theoretical YieldEstimate the maximum ammonia that can form from a known reactant amount.
- Balance Another Chemical EquationUse the equation balancer for any other reaction.
Related Chemical Equations
Browse nearby balanced-equation examples and common homework reactions.
Frequently Asked Questions
What is the balanced equation for N2 + H2 → NH3?
The balanced equation is N₂ + 3H₂ → 2NH₃. The smallest whole-number coefficients are 1 for N₂, 3 for H₂, and 2 for NH₃.
What are the coefficients for N2 + H2 → NH3?
The coefficients are 1 : 3 : 2. That means N₂ + 3H₂ → 2NH₃, with an implied coefficient of 1 before N₂.
How do you balance N2 + H2 → NH3?
Balance nitrogen first by placing 2 before NH₃. That gives 2 nitrogen atoms on each side. Then 2NH₃ contains 6 hydrogen atoms, so place 3 before H₂ to make N₂ + 3H₂ → 2NH₃.
What is the mole ratio of N2 to H2?
The mole ratio of N₂ to H₂ is 1 : 3. One mole of nitrogen gas reacts with three moles of hydrogen gas.
What is the mole ratio of N2 to NH3?
The mole ratio of N₂ to NH₃ is 1 : 2. One mole of nitrogen gas can produce two moles of ammonia when enough hydrogen is available.
What type of reaction is N2 + H2 → NH3?
N₂ + H₂ → NH₃ is a synthesis, or combination, reaction because two reactants combine to form one compound: ammonia.