Balancing Equations Worksheet featuring 37 chemical reactions to balance, designed for educational use.

Let’s solve each equation one by one. We’ll balance them by making sure the number of atoms of each element is the same on both sides of the arrow.

We’ll go step by step for each problem, but since there are 37 equations, I’ll show you how to do a few key ones in detail, then give all answers at the end so you can check your work.

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Example: Problem #1

H₃PO₄ + KOH → K₃PO₄ + H₂O

Left side:
- H: 3 (from H₃PO₄) + 1 (from KOH) = 4? Wait — actually, we don’t know coefficients yet. Let’s assign variables.

Try putting a 1 in front of H₃PO₄ and see what happens.

Assume:
1 H₃PO₄ + ? KOH → ? K₃PO₄ + ? H₂O

Phosphorus: 1 on left → need 1 K₃PO₄ on right.

So now:
1 H₃PO₄ + ? KOH → 1 K₃PO₄ + ? H₂O

Potassium: 3 on right → need 3 KOH on left.

Now:
1 H₃PO₄ + 3 KOH → 1 K₃PO₄ + ? H₂O

Hydrogen: Left = 3 (from H₃PO₄) + 3×1 (from 3 KOH) = 6 H
Right: Only in H₂O → so need 3 H₂O to get 6 H.

Oxygen: Check it too.
Left: 4 (from H₃PO₄) + 3×1 (from 3 KOH) = 7 O
Right: 4 (from K₃PO₄) + 3×1 (from 3 H₂O) = 7 O → Good!

✔ Balanced: 1 H₃PO₄ + 3 KOH → 1 K₃PO₄ + 3 H₂O

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Problem #2

K + B₂O₃ → K₂O + B

Left: K=1, B=2, O=3
Right: K=2, O=1, B=1

Need to balance B first. Put 2 in front of B on right.

→ K + B₂O₃ → K₂O + 2B

Now B is balanced.

Oxygen: 3 on left → need 3 K₂O on right? But that gives 6 K.

Try:
Put 3 in front of K₂O → then O=3, K=6

So left needs 6 K.

→ 6K + B₂O₃ → 3K₂O + 2B

Check:
K: 6 = 6
B: 2 = 2
O: 3 = 3 → ✔

Balanced: 6 K + 1 B₂O₃ → 3 K₂O + 2 B

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Problem #3

HCl + NaOH → NaCl + H₂O

This is already balanced!
H: 1+1=2 on left, 2 on right
Cl: 1=1
Na: 1=1
O: 1=1

✔ 1 HCl + 1 NaOH → 1 NaCl + 1 H₂O

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You can use this method for all: pick an element that appears in only one compound on each side, balance it, then move to others.

Sometimes you have to go back and adjust if something gets unbalanced.

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Here are ALL the balanced equations with coefficients filled in:

1) 1 H₃PO₄ + 3 KOH → 1 K₃PO₄ + 3 H₂O
2) 6 K + 1 B₂O₃ → 3 K₂O + 2 B
3) 1 HCl + 1 NaOH → 1 NaCl + 1 H₂O
4) 10 Na + 2 NaNO₃ → 6 Na₂O + 1 N₂
5) 4 C + 1 S₈ → 4 CS₂
6) 4 Na + 1 O₂ → 2 Na₂O
7) 2 N₂ + 5 O₂ → 2 N₂O₅
8) 2 H₃PO₄ + 3 Mg(OH)₂ → 1 Mg₃(PO₄)₂ + 6 H₂O
9) 2 NaOH + 1 H₂CO₃ → 1 Na₂CO₃ + 2 H₂O
10) 1 KOH + 1 HBr → 1 KBr + 1 H₂O
11) 4 Na + 1 O₂ → 2 Na₂O
12) 2 Al(OH)₃ + 3 H₂CO₃ → 1 Al₂(CO₃)₃ + 6 H₂O
13) 16 Al + 3 S₈ → 8 Al₂S₃
14) 6 Cs + 1 N₂ → 2 Cs₃N
15) 1 Mg + 1 Cl₂ → 1 MgCl₂
16) 10 Rb + 2 RbNO₃ → 6 Rb₂O + 1 N₂
17) 2 C₆H₆ + 15 O₂ → 12 CO₂ + 6 H₂O
18) 1 N₂ + 3 H₂ → 2 NH₃
19) 2 C₁₀H₂₂ + 31 O₂ → 20 CO₂ + 22 H₂O
20) 1 Al(OH)₃ + 3 HBr → 1 AlBr₃ + 3 H₂O
21) 1 CH₃CH₂CH₂CH₃ + 13/2 O₂ → 4 CO₂ + 5 H₂O → multiply by 2: 2 C₄H₁₀ + 13 O₂ → 8 CO₂ + 10 H₂O
*(Note: C₄H₁₀ is butane; written as CH₃CH₂CH₂CH₃)*
22) 1 C₃H₈ + 5 O₂ → 3 CO₂ + 4 H₂O
23) 3 Li + 1 AlCl₃ → 3 LiCl + 1 Al
24) 2 C₂H₆ + 7 O₂ → 4 CO₂ + 6 H₂O
25) 3 NH₄OH + 1 H₃PO₄ → 1 (NH₄)₃PO₄ + 3 H₂O
26) 3 Rb + 1 P → 1 Rb₃P
27) 1 CH₄ + 2 O₂ → 1 CO₂ + 2 H₂O
28) 2 Al(OH)₃ + 3 H₂SO₄ → 1 Al₂(SO₄)₃ + 6 H₂O
29) 2 Na + 1 Cl₂ → 2 NaCl
30) 16 Rb + 1 S₈ → 8 Rb₂S
31) 2 H₃PO₄ + 3 Ca(OH)₂ → 1 Ca₃(PO₄)₂ + 6 H₂O
32) 1 NH₃ + 1 HCl → 1 NH₄Cl
33) 2 Li + 2 H₂O → 2 LiOH + 1 H₂
34) 1 Ca₃(PO₄)₂ + 3 SiO₂ + 5 C → 3 CaSiO₃ + 5 CO + 2 P
35) 4 NH₃ + 3 O₂ → 2 N₂ + 6 H₂O
36) 4 FeS₂ + 11 O₂ → 2 Fe₂O₃ + 8 SO₂
37) 5 C + 2 SO₂ → 1 CS₂ + 4 CO

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Final Answer:
All equations balanced with coefficients as listed above. You can copy them directly into your worksheet. Double-check any that look tricky by counting atoms on both sides!