Stormy Reactions
Balance the equations for lightning-induced nitrogen fixation.
What this lesson covers
Why it matters
A lightning bolt strikes, delivering enough energy to break the stubborn bonds of atmospheric nitrogen. The air instantly fills with a sharp, pungent smell as new compounds form.
The idea in plain words
Verify the stoichiometry: 2 molecules of NO react with 1 molecule of O₂ to form 2 molecules of NO₂.
Predict first
Why do nitrogen and oxygen react during a storm but not on a calm day?
Nitrogen is inert at room temperature. The massive energy from lightning breaks the triple bond in N₂, allowing it to combine with oxygen.
- Lightning provides the activation energy to break strong N≡N bonds — correct
- Nitrogen is more reactive than oxygen
- The rain washes them together
- They react spontaneously at room temperature
What you do
Observe the color change as nitric oxide meets oxygen. Note the specific appearance of the product.
Check yourself
What is the visible evidence of NO₂ formation in this reaction?
The reaction data specifies NO₂ is a reddish-brown, pungent gas.
Which equation correctly represents the formation of nitrogen dioxide from nitric oxide?
The balanced equation requires 2 moles of NO and 1 mole of O₂ to produce 2 moles of NO₂.
After the storm, how do these nitrogen oxides end up helping plants grow?
The nitrogen oxides dissolve in rain to form dilute nitric acid, which becomes nitrates in the soil — a natural fertiliser that plant roots absorb.
- A colorless gas is produced
- A reddish-brown gas with a pungent odor — correct
- A white solid precipitate
- A blue liquid forms
- NO + O₂ → NO₂
- 2NO + O₂ → 2NO₂ — correct
- N₂ + O₂ → 2NO₂
- 2NO + 2O₂ → 2NO₂
- They dissolve in rain to form nitric acid, which becomes nitrates in the soil for roots to absorb — correct
- Plants breathe in NO₂ gas directly through their leaves
- The lightning's heat makes seeds sprout faster