q10 How to determine the balanced chemical equation?

Carbon combustion 🔥

C + O₂ → CO₂ 

Methane combustion 🔥

CH₄ + 2O₂ → CO₂ + 2H₂O

A chemical equation contains an arrow, plus signs, and formulas of chemical species.

+ means “and”.

→ means “react to form”.

The arrow separates the reactants 🧪 from the products 🧪.

II— Conditions for being balanced ✅

A chemical equation is balanced when:

The number of atoms, or elements, of each kind is identical before and after the arrow.

Example:
Methane combustion 🔥
CH₄ + 2O₂ → CO₂ + 2H₂O 1C₁H₄ + 2O₂ → 1C₁O₂ + 2H₂O₁

Reactants:
C: 1 × 1 = 1
H: 1 × 4 = 4
O: 2 × 2 = 4

Products:
C: 1 × 1 = 1
H: 2 × 2 = 4
O: 1 × 2 + 2 × 1 = 4

This chemical equation is balanced.
The reactants and the products contain 1 carbon atom, 4 hydrogen atoms, and 4 oxygen atoms.

III— Balanced or not balanced? 🧠

Butane combustion 🔥
C₄H₁₀ + 4O₂ → 4CO₂ + 5H₂O 1C₄H₁₀ + 4O₂ → 4C₁O₂ + 5H₂O₁

Reactants:
C: 1 × 4 = 4
H: 1 × 10 = 10
O: 4 × 2 = 8

Products:
C: 4 × 1 = 4
H: 5 × 2 = 10
O: 4 × 2 + 5 × 1 = 13

This chemical equation is not balanced because the number of oxygen atoms is not the same in the reactants and in the products (8 < 13).

IV— Balanced or not balanced? 🧠

Butane combustion 🔥
2C₄H₁₀ + 13O₂ → 8CO₂ + 10H₂O 2C₄H₁₀ + 13O₂ → 8C₁O₂ + 10H₂O₁

Reactants:
C: 2 × 4 = 8
H: 2 × 10 = 20
O: 13 × 2 = 26

Products:
C: 8 × 1 = 8
H: 10 × 2 = 20
O: 8 × 2 + 10 × 1 = 26

This chemical equation is balanced.
The reactants and the products contain 8 carbon atoms, 20 hydrogen atoms, and 26 oxygen atoms.

How do you determine the balanced chemical equation?

I— Examples of chemical equations 🧪

II— Conditions for being balanced ✅

III— Balanced or not balanced? 🧠

IV— Balanced or not balanced? 🧠