Balancing Equations Worksheet | Math = Love - Free Printable

I'll solve these three chemical equation balancing problems step by step.

Problem 1: CH₄ + O₂ → CO₂ + H₂O

Let me count atoms on each side:
- Left side: C=1, H=4, O=2
- Right side: C=1, H=2, O=3 (2 from CO₂ + 1 from H₂O)

The carbon is already balanced (1 on each side).
Hydrogen needs balancing: 4 on left, 2 on right. Put a 2 in front of H₂O.
Now: CH₄ + O₂ → CO₂ + 2H₂O

Recount:
- Left: C=1, H=4, O=2
- Right: C=1, H=4, O=4 (2 from CO₂ + 2 from 2H₂O)

Oxygen needs balancing: 2 on left, 4 on right. Put a 2 in front of O₂.

Final: CH₄ + 2O₂ → CO₂ + 2H₂O

Check: C=1, H=4, O=4 on both sides ✓

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Problem 2: C₃H₈ + O₂ → CO₂ + H₂O

Count atoms:
- Left: C=3, H=8, O=2
- Right: C=1, H=2, O=3

Balance carbon first: Put 3 in front of CO₂
C₃H₈ + O₂ → 3CO₂ + H₂O

Balance hydrogen: Put 4 in front of H₂O (to get 8 H)
C₃H₈ + O₂ → 3CO₂ + 4H₂O

Count oxygen on right: 3×2 + 4×1 = 6 + 4 = 10 oxygen atoms
Put 5 in front of O₂ to get 10 oxygen on left

Final: C₃H₈ + 5O₂ → 3CO₂ + 4H₂O

Check: C=3, H=8, O=10 on both sides ✓

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Problem 3: C₈H₁₈ + O₂ → CO₂ + H₂O

Count atoms:
- Left: C=8, H=18, O=2
- Right: C=1, H=2, O=3

Balance carbon: Put 8 in front of CO₂
CH₁₈ + O₂ → 8CO₂ + H₂O

Balance hydrogen: Put 9 in front of H₂O (to get 18 H)
C₈H₁₈ + O₂ → 8CO₂ + 9H₂O

Count oxygen on right: 8×2 + 9×1 = 16 + 9 = 25 oxygen atoms

To get 25 oxygen on the left, I need 25/2 = 12.5 molecules of O₂. But we want whole numbers!

Multiply everything by 2:
2C₈H₁₈ + 25O₂ → 16CO₂ + 18H₂O

Check:
- Left: C=16, H=36, O=50
- Right: C=16, H=36, O=32+18=50 ✓

Final Answer:
1. 1CH₄ + 2O₂ → 1CO₂ + 2H₂O
2. 1C₃H₈ + 5O₂ → 3CO₂ + 4H₂O
3. 2C₈H₁₈ + 25O₂ → 16CO₂ + 18H₂O