Free Printable Balancing and Classifying Chemical Equations Worksheets - Free Printable

To balance these decomposition reactions, we need to make sure that the number of atoms of each element is the same on both sides of the equation. We do this by adding coefficients (numbers in front of the chemical formulas).

Let’s go through each one:

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i. PbSO₄ → PbSO₃ + O₂

Left: Pb=1, S=1, O=4
Right: Pb=1, S=1, O=3+2=5 → Not balanced

Try:
2PbSO₄ → 2PbSO₃ + O₂
Left: Pb=2, S=2, O=8
Right: Pb=2, S=2, O=6+2=8 → Balanced ✔

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ii. NaF → Na + F₂

Left: Na=1, F=1
Right: Na=1, F=2 → Not balanced

Try:
2NaF → 2Na + F₂
Left: Na=2, F=2
Right: Na=2, F=2 → Balanced ✔

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iii. Li₃N → Li + N₂

Left: Li=3, N=1
Right: Li=1, N=2 → Not balanced

Try:
2Li₃N → 6Li + N₂
Left: Li=6, N=2
Right: Li=6, N=2 → Balanced ✔

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iv. AgOH → Ag₂O + H₂O

Left: Ag=1, O=1, H=1
Right: Ag=2, O=2, H=2 → Not balanced

Try:
2AgOH → Ag₂O + H₂O
Left: Ag=2, O=2, H=2
Right: Ag=2, O=1+1=2, H=2 → Balanced ✔

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v. NH₃ → N₂ + H₂

Left: N=1, H=3
Right: N=2, H=2 → Not balanced

Try:
2NH₃ → N₂ + 3H₂
Left: N=2, H=6
Right: N=2, H=6 → Balanced ✔

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vi. Al₂S₃ → Al + S

Left: Al=2, S=3
Right: Al=1, S=1 → Not balanced

Try:
Al₂S₃ → 2Al + 3S
Left: Al=2, S=3
Right: Al=2, S=3 → Balanced ✔

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vii. Al₂O₃ → Al + O₂

Left: Al=2, O=3
Right: Al=1, O=2 → Not balanced

Try:
2Al₂O₃ → 4Al + 3O₂
Left: Al=4, O=6
Right: Al=4, O=6 → Balanced ✔

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viii. H₂O₂ → H₂O + O₂

Left: H=2, O=2
Right: H=2, O=1+2=3 → Not balanced

Try:
2H₂O₂ → 2H₂O + O₂
Left: H=4, O=4
Right: H=4, O=2+2=4 → Balanced ✔

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ix. NaCl → Na + Cl₂

Left: Na=1, Cl=1
Right: Na=1, Cl=2 → Not balanced

Try:
2NaCl → 2Na + Cl₂
Left: Na=2, Cl=2
Right: Na=2, Cl=2 → Balanced ✔

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x. H₃PO₄ → H₄P₂O₇ + H₂O

Left: H=3, P=1, O=4
Right: H=4+2=6, P=2, O=7+1=8 → Not balanced

Try:
2H₃PO₄ → H₄P₂O₇ + H₂O
Left: H=6, P=2, O=8
Right: H=4+2=6, P=2, O=7+1=8 → Balanced ✔

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xi. NH₄NO₂ → N₂ + H₂O

Left: N=2, H=4, O=2
Right: N=2, H=2, O=1 → Not balanced

Try:
NH₄NO₂ → N₂ + 2H₂O
Left: N=2, H=4, O=2
Right: N=2, H=4, O=2 → Balanced ✔

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xii. N₂O₅ → N₂ + O₂

Left: N=2, O=5
Right: N=2, O=2 → Not balanced

Try:
2N₂O₅ → 2N₂ + 5O₂
Left: N=4, O=10
Right: N=4, O=10 → Balanced ✔

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xiii. Fe₂O₃ → Fe + O₂

Left: Fe=2, O=3
Right: Fe=1, O=2 → Not balanced

Try:
2Fe₂O₃ → 4Fe + 3O₂
Left: Fe=4, O=6
Right: Fe=4, O=6 → Balanced ✔

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xiv. KClO₃ → KCl + O₂

Left: K=1, Cl=1, O=3
Right: K=1, Cl=1, O=2 → Not balanced

Try:
2KClO₃ → 2KCl + 3O₂
Left: K=2, Cl=2, O=6
Right: K=2, Cl=2, O=6 → Balanced ✔

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xv. Na₂CO₃ → Na₂O + CO₂

Left: Na=2, C=1, O=3
Right: Na=2, C=1, O=1+2=3 → Already balanced!

So:
Na₂CO₃ → Na₂O + CO₂ ✔

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Final Answer:
i. 2 PbSO₄ → 2 PbSO₃ + 1 O₂
ii. 2 NaF → 2 Na + 1 F₂
iii. 2 Li₃N → 6 Li + 1 N₂
iv. 2 AgOH → 1 Ag₂O + 1 H₂O
v. 2 NH₃ → 1 N₂ + 3 H₂
vi. 1 Al₂S₃ → 2 Al + 3 S
vii. 2 Al₂O₃ → 4 Al + 3 O₂
viii. 2 H₂O₂ → 2 H₂O + 1 O₂
ix. 2 NaCl → 2 Na + 1 Cl₂
x. 2 H₃PO₄ → 1 H₄P₂O₇ + 1 H₂O
xi. 1 NH₄NO₂ → 1 N₂ + 2 H₂O
xii. 2 N₂O₅ → 2 N₂ + 5 O₂
xiii. 2 Fe₂O₃ → 4 Fe + 3 O₂
xiv. 2 KClO₃ → 2 KCl + 3 O₂
xv. 1 Na₂CO₃ → 1 Na₂O + 1 CO₂