Balance Cu + HNO₃ → Cu(NO₃)₂ + NO₂ + H₂O
Cu(s) + 4 HNO₃(aq) → Cu(NO₃)₂(aq) + 2 NO₂(g) + 2 H₂O(l)
Balance an equation
Cu(s)+4HNO₃(aq)→Cu(NO₃)₂(aq)+2NO₂(g)+2H₂O(l)
Balanced
Atoms on each side
| Atom | As writtenleft : right | Balancedleft : right |
|---|---|---|
| Cu | 1:1 | 1:1 |
| H | 1:2 | 4:4 |
| N | 1:3 | 4:4 |
| O | 3:9 | 12:12 |
Check atoms
How to balance it, step by step
- Count the atoms of each element on both sides, as written.
- This one needs two coefficients at once, so write a letter for each: a Cu, b HNO₃, c Cu(NO₃)₂, d NO₂, e H₂O.
- Cu: a = c
- H: b = 2e
- N: b = 2c + d
- O: 3b = 6c + 2d + e
- Solve, keeping the smallest whole numbers: a = 1, b = 4, c = 1, d = 2, e = 2.
- Check: Cu 1 = 1, H 4 = 4, N 4 = 4, O 12 = 12. Balanced.
What happens
It is a redox reaction: one substance is oxidised while another is reduced. Concentrated nitric acid oxidises copper, giving a blue solution of copper nitrate and brown fumes of nitrogen dioxide. Copper does not give hydrogen with nitric acid.
Copper and nitric acid: quick answers
What is the balanced equation for copper and nitric acid?
Cu(s) + 4 HNO₃(aq) → Cu(NO₃)₂(aq) + 2 NO₂(g) + 2 H₂O(l). The coefficients are 1, 4, 1, 2 and 2. Each side then has 1 Cu, 4 H, 4 N and 12 O.
What type of reaction is copper and nitric acid?
It is a redox reaction: one substance is oxidised while another is reduced. Concentrated nitric acid oxidises copper, giving a blue solution of copper nitrate and brown fumes of nitrogen dioxide. Copper does not give hydrogen with nitric acid.
How do you balance Cu + HNO₃ → Cu(NO₃)₂ + NO₂ + H₂O?
This one needs two coefficients at once, so write a letter for each: a Cu, b HNO₃, c Cu(NO₃)₂, d NO₂, e H₂O. Cu: a = c H: b = 2e N: b = 2c + d O: 3b = 6c + 2d + e Solve, keeping the smallest whole numbers: a = 1, b = 4, c = 1, d = 2, e = 2. Never change a subscript, because that would change the substance.