Balancing Equations Worksheet from Everett Community College Tutoring Center.

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 problems, I’ll show you how to do a few key ones and then give you all the answers at the end — so you can check your work or learn from the pattern.

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Problem 1: H₃PO₄ + KOH → K₃PO₄ + H₂O

Left side:
H: 3 (from H₃PO₄) + 1 (from KOH) = 4? Wait — no! We have coefficients to add. Let’s think:

We need 3 K on right → so put 3 in front of KOH.

Now left:
K: 3
O: 4 (from H₃PO) + 3 (from 3KOH) = 7
H: 3 (from H₃PO₄) + 3 (from 3KOH) = 6

Right:
K₃PO₄ has 3K, 1P, 4O
H₂O has 2H, 1O → we need 3 H₂O to get 6H and 3O → total O on right: 4 + 3 = 7 ✔

So:
1 H₃PO₄ + 3 KOH → 1 K₃PO₄ + 3 H₂O

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Problem 2: K + B₂O₃ → K₂O + B

Left: K, B=2, O=3
Right: K=2, O=1, B=1 → need to balance.

Put 3 in front of K₂O → now O=3, K=6
Then put 6 in front of K on left → K=6
Put 2 in front of B on right → B=2

So:
6 K + 1 B₂O₃ → 3 K₂O + 2 B

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Problem 3: HCl + NaOH → NaCl + H₂O

Already balanced!
H: 1+1=2, Cl:1, Na:1, O:1 → right: Na:1, Cl:1, H:2, O:1 ✔

So:
1 HCl + 1 NaOH → 1 NaCl + 1 H₂O

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Problem 4: Na + NaNO₃ → Na₂O + N₂

Left: Na, Na, N, O₃ → total Na=2? Not yet.

Try:
Put 10 Na on left? Too messy.

Better way:
N₂ on right → need 2 N → so 2 NaNO₃ on left → gives 2Na, 2N, 6O

Now right: Na₂O → to get 6O, need 6 Na₂O → that’s 12 Na

Left: from 2 NaNO₃ → 2 Na, plus x Na → total Na = 2 + x

Set 2 + x = 12 → x = 10

So:
10 Na + 2 NaNO₃ → 6 Na₂O + 1 N₂

Check:
Left: Na=10+2=12, N=2, O=6
Right: Na=12, O=6, N=2 ✔

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You see the pattern? We adjust coefficients until atoms match.

Since doing all 37 step-by-step here would be too long, I’ll give you the full correct balanced equations below — verified carefully.

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Final Answer:

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
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) 2 Ca₃(PO₄)₂ + 6 SiO₂ + 10 C → 6 CaSiO₃ + 10 CO + 4 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

✔ All equations are balanced with smallest whole numbers. Double-checked atom counts for each.