50 Balancing Equations Worksheet Answers Chemistry | Chessmuseum ... - Free Printable

Task: Balance the chemical equations provided in the worksheet.

Balancing chemical equations involves ensuring that the number of atoms of each element is the same on both sides of the equation. This is done by adjusting the coefficients (numbers placed in front of the chemical formulas) while keeping the subscripts unchanged.

Below are the balanced equations for each problem, along with explanations for selected ones.

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1. Ca + O₂ → CaO

- Initial Equation: Ca + O₂ → CaO
- Analysis:
- Left side: 1 Ca, 2 O
- Right side: 1 Ca, 1 O
- Balancing:
- To balance oxygen, we need 2 CaO molecules.
- Balanced Equation: 2Ca + O₂ → 2CaO

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2. H₂ + Cl₂ → HCl

- Initial Equation: H₂ + Cl₂ → HCl
- Analysis:
- Left side: 2 H, 2 Cl
- Right side: 1 H, 1 Cl
- Balancing:
- To balance hydrogen and chlorine, we need 2 HCl molecules.
- Balanced Equation: H₂ + Cl₂ → 2HCl

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3. P₄ + S₈ → P₂S₅

- Initial Equation: P₄ + S₈ → P₂S₅
- Analysis:
- Left side: 4 P, 8 S
- Right side: 2 P, 5 S
- Balancing:
- To balance phosphorus (P), we need 2 P₂S₅ molecules.
- To balance sulfur (S), we adjust the coefficient of S₈.
- Balanced Equation: P₄ + 5S₈ → 4P₂S₅

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4. CO + O₂ → CO₂

- Initial Equation: CO + O₂ → CO₂
- Analysis:
- Left side: 1 C, 1 O, 2 O
- Right side: 1 C, 2 O
- Balancing:
- To balance oxygen, we need 1/2 O₂ molecule, but since we cannot use fractions, we multiply the entire equation by 2.
- Balanced Equation: 2CO + O₂ → 2CO₂

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5. C₂H₆ + O₂ → CO₂ + H₂O

- Initial Equation: C₂H₆ + O₂ → CO₂ + H₂O
- Analysis:
- Left side: 2 C, 6 H, 2 O
- Right side: 1 C, 2 O, 2 H, 1 O
- Balancing:
- Balance carbon first: 2 CO₂ molecules.
- Balance hydrogen next: 3 H₂O molecules.
- Balance oxygen last: 7/2 O₂ molecules, so multiply everything by 2.
- Balanced Equation: 2C₂H₆ + 7O₂ → 4CO₂ + 6H₂O

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6. C₂H₅OH + O₂ → CO₂ + H₂O

- Initial Equation: C₂H₅OH + O₂ → CO₂ + H₂O
- Analysis:
- Left side: 2 C, 6 H, 1 O
- Right side: 1 C, 2 O, 2 H, 1 O
- Balancing:
- Balance carbon first: 2 CO₂ molecules.
- Balance hydrogen next: 3 H₂O molecules.
- Balance oxygen last: 3 O₂ molecules.
- Balanced Equation: C₂H₅OH + 3O₂ → 2CO₂ + 3H₂O

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7. FeS₂ + O₂ → Fe₂O₃ + SO₂

- Initial Equation: FeS₂ + O₂ → Fe₂O₃ + SO₂
- Analysis:
- Left side: 1 Fe, 2 S, 2 O
- Right side: 2 Fe, 3 O, 1 S, 2 O
- Balancing:
- Balance iron (Fe): 2 FeS₂ molecules.
- Balance sulfur (S): 4 SO₂ molecules.
- Balance oxygen (O): 11/2 O₂ molecules, so multiply everything by 2.
- Balanced Equation: 4FeS₂ + 11O₂ → 2Fe₂O₃ + 8SO₂

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8. P₄ + O₃ → P₂O₅

- Initial Equation: P₄ + O₃ → P₂O₅
- Analysis:
- Left side: 4 P, 3 O
- Right side: 2 P, 5 O
- Balancing:
- Balance phosphorus (P): 2 P₂O₅ molecules.
- Balance oxygen (O): 5/3 O₃ molecules, so multiply everything by 3.
- Balanced Equation: 3P₄ + 10O₃ → 6P₂O₅

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9. NH₃ + O₂ → N₂O₃ + H₂O

- Initial Equation: NH₃ + O₂ → N₂O₃ + H₂O
- Analysis:
- Left side: 1 N, 3 H, 2 O
- Right side: 2 N, 3 O, 2 H, 1 O
- Balancing:
- Balance nitrogen (N): 2 NH₃ molecules.
- Balance hydrogen (H): 3 H₂O molecules.
- Balance oxygen (O): 4 O₂ molecules.
- Balanced Equation: 4NH₃ + 7O₂ → 2N₂O₃ + 6H₂O

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10. Si₅H₁₁ + Br₂ → Si + HBr

- Initial Equation: Si₅H₁₁ + Br₂ → Si + HBr
- Analysis:
- Left side: 5 Si, 11 H, 2 Br
- Right side: 1 Si, 1 H, 1 Br
- Balancing:
- Balance silicon (Si): 5 Si molecules.
- Balance hydrogen (H): 11 HBr molecules.
- Balance bromine (Br): 11/2 Br₂ molecules, so multiply everything by 2.
- Balanced Equation: 2Si₅H₁₁ + 11Br₂ → 10Si + 22HBr

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11. FeCl₃ + NaOH → Fe(OH)₃ + NaCl

- Initial Equation: FeCl₃ + NaOH → Fe(OH)₃ + NaCl
- Analysis:
- Left side: 1 Fe, 3 Cl, 1 Na, 1 O, 1 H
- Right side: 1 Fe, 3 O, 3 H, 1 Na, 1 Cl
- Balancing:
- Balance hydroxide (OH): 3 NaOH molecules.
- Balance sodium (Na): 3 NaCl molecules.
- Balanced Equation: FeCl₃ + 3NaOH → Fe(OH)₃ + 3NaCl

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12. Fe + H₂O → Fe₂O₃ + H₂

- Initial Equation: Fe + H₂O → Fe₂O₃ + H₂
- Analysis:
- Left side: 1 Fe, 2 H, 1 O
- Right side: 2 Fe, 3 O, 2 H
- Balancing:
- Balance iron (Fe): 2 Fe molecules.
- Balance oxygen (O): 3 H₂O molecules.
- Balance hydrogen (H): 3 H₂ molecules.
- Balanced Equation: 3Fe + 4H₂O → Fe₂O₃ + 4H₂

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13. C₁₀H₂₂ + Cl₂ → C + HCl

- Initial Equation: C₁₀H₂₂ + Cl₂ → C + HCl
- Analysis:
- Left side: 10 C, 22 H, 2 Cl
- Right side: 1 C, 1 H, 1 Cl
- Balancing:
- Balance carbon (C): 10 C molecules.
- Balance hydrogen (H): 22 HCl molecules.
- Balance chlorine (Cl): 11 Cl₂ molecules.
- Balanced Equation: C₁₀H₂₂ + 11Cl₂ → 10C + 22HCl

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14. FeCl₃ + Na₂SO₄ → Fe₂(SO₄)₃ + NaCl

- Initial Equation: FeCl₃ + Na₂SO₄ → Fe₂(SO₄)₃ + NaCl
- Analysis:
- Left side: 1 Fe, 3 Cl, 2 Na, 1 S, 4 O
- Right side: 2 Fe, 3 S, 12 O, 1 Na, 1 Cl
- Balancing:
- Balance iron (Fe): 2 FeCl₃ molecules.
- Balance sulfate (SO₄): 3 Na₂SO₄ molecules.
- Balance sodium (Na): 6 NaCl molecules.
- Balanced Equation: 2FeCl₃ + 3Na₂SO₄ → Fe₂(SO₄)₃ + 6NaCl

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15. Al + HNO₃ → Al(NO₃)₃ + H₂

- Initial Equation: Al + HNO₃ → Al(NO₃)₃ + H₂
- Analysis:
- Left side: 1 Al, 1 H, 1 N, 3 O
- Right side: 1 Al, 3 N, 9 O, 2 H
- Balancing:
- Balance aluminum (Al): 2 Al molecules.
- Balance nitrate (NO₃): 6 HNO₃ molecules.
- Balance hydrogen (H): 3 H₂ molecules.
- Balanced Equation: 2Al + 6HNO₃ → 2Al(NO₃)₃ + 3H₂

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16. K + H₂O → KOH + H₂

- Initial Equation: K + H₂O → KOH + H₂
- Analysis:
- Left side: 1 K, 2 H, 1 O
- Right side: 1 K, 1 O, 2 H
- Balancing:
- The equation is already balanced.
- Balanced Equation: 2K + 2H₂O → 2KOH + H₂

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17. C₃H₈ + S₈ → CS₂ + H₂S

- Initial Equation: C₃H₈ + S₈ → CS₂ + H₂S
- Analysis:
- Left side: 3 C, 8 H, 8 S
- Right side: 1 C, 2 S, 2 H, 1 S
- Balancing:
- Balance carbon (C): 3 CS₂ molecules.
- Balance hydrogen (H): 4 H₂S molecules.
- Balance sulfur (S): 5 S₈ molecules.
- Balanced Equation: 3C₃H₈ + 5S₈ → 9CS₂ + 12H₂S

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18. MgCl₂ + Al(OH)₃ → AlCl₃ + Mg(OH)₂

- Initial Equation: MgCl₂ + Al(OH)₃ → AlCl₃ + Mg(OH)₂
- Analysis:
- Left side: 1 Mg, 2 Cl, 1 Al, 3 O, 3 H
- Right side: 1 Al, 3 Cl, 1 Mg, 2 O, 2 H
- Balancing:
- Balance magnesium (Mg): 2 MgCl₂ molecules.
- Balance aluminum (Al): 2 Al(OH)₃ molecules.
- Balance chloride (Cl): 2 AlCl₃ molecules.
- Balance hydroxide (OH): 3 Mg(OH)₂ molecules.
- Balanced Equation: 2MgCl₂ + 2Al(OH)₃ → 2AlCl₃ + 3Mg(OH)₂

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19. ZnFeS₂ + O₂ → Zn + FeO + SO₂

- Initial Equation: ZnFeS₂ + O₂ → Zn + FeO + SO₂
- Analysis:
- Left side: 1 Zn, 1 Fe, 2 S, 2 O
- Right side: 1 Zn, 1 Fe, 1 O, 2 S, 2 O
- Balancing:
- Balance zinc (Zn): 1 Zn molecule.
- Balance iron (Fe): 1 FeO molecule.
- Balance sulfur (S): 2 SO₂ molecules.
- Balance oxygen (O): 5/2 O₂ molecules, so multiply everything by 2.
- Balanced Equation: 2ZnFeS₂ + 5O₂ → 2Zn + 2FeO + 4SO₂

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20. P₄O₁₀ + H₂O → H₃PO₄

- Initial Equation: P₄O₁₀ + H₂O → H₃PO₄
- Analysis:
- Left side: 4 P, 10 O, 2 H
- Right side: 1 P, 4 O, 3 H
- Balancing:
- Balance phosphorus (P): 4 H₃PO₄ molecules.
- Balance hydrogen (H): 6 H₂O molecules.
- Balanced Equation: P₄O₁₀ + 6H₂O → 4H₃PO₄

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21. KClO₃ → KCl + KClO₄

- Initial Equation: KClO₃ → KCl + KClO₄
- Analysis:
- Left side: 1 K, 1 Cl, 3 O
- Right side: 1 K, 1 Cl, 4 O
- Balancing:
- Balance chlorine (Cl): 4 KClO₃ molecules.
- Balance potassium (K): 4 KCl molecules.
- Balance oxygen (O): 3 KClO₄ molecules.
- Balanced Equation: 4KClO₃ → 3KClO₄ + KCl

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22. Mg₃N₂ + H₂O → Mg(OH)₂ + NH₃

- Initial Equation: Mg₃N₂ + H₂O → Mg(OH)₂ + NH₃
- Analysis:
- Left side: 3 Mg, 2 N, 2 H, 1 O
- Right side: 1 Mg, 2 O, 2 H, 1 N
- Balancing:
- Balance magnesium (Mg): 3 Mg(OH)₂ molecules.
- Balance nitrogen (N): 2 NH₃ molecules.
- Balance hydrogen (H): 6 H₂O molecules.
- Balanced Equation: Mg₃N₂ + 6H₂O → 3Mg(OH)₂ + 2NH₃

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Final Answer

The balanced equations are as follows:

1. 2Ca + O₂ → 2CaO
2. H₂ + Cl₂ → 2HCl
3. P₄ + 5S₈ → 4P₂S₅
4. 2CO + O₂ → 2CO₂
5. 2C₂H₆ + 7O₂ → 4CO₂ + 6H₂O
6. C₂H₅OH + 3O₂ → 2CO₂ + 3H₂O
7. 4FeS₂ + 11O₂ → 2Fe₂O₃ + 8SO₂
8. 3P₄ + 10O₃ → 6P₂O₅
9. 4NH₃ + 7O₂ → 2N₂O₃ + 6H₂O
10. 2Si₅H₁₁ + 11Br₂ → 10Si + 22HBr
11. FeCl₃ + 3NaOH → Fe(OH)₃ + 3NaCl
12. 3Fe + 4H₂O → Fe₂O₃ + 4H₂
13. C₁₀H₂₂ + 11Cl₂ → 10C + 22HCl
14. 2FeCl₃ + 3Na₂SO₄ → Fe₂(SO₄)₃ + 6NaCl
15. 2Al + 6HNO₃ → 2Al(NO₃)₃ + 3H₂
16. 2K + 2H₂O → 2KOH + H₂
17. 3C₃H₈ + 5S₈ → 9CS₂ + 12H₂S
18. 2MgCl₂ + 2Al(OH)₃ → 2AlCl₃ + 3Mg(OH)₂
19. 2ZnFeS₂ + 5O₂ → 2Zn + 2FeO + 4SO₂
20. P₄O₁₀ + 6H₂O → 4H₃PO₄
21. 4KClO₃ → 3KClO₄ + KCl
22. Mg₃N₂ + 6H₂O → 3Mg(OH)₂ + 2NH₃

Boxed Final Answer:
\boxed{
\begin{aligned}
&1. \, 2Ca + O_2 \rightarrow 2CaO \\
&2. \, H_2 + Cl_2 \rightarrow 2HCl \\
&3. \, P_4 + 5S_8 \rightarrow 4P_2S_5 \\
&4. \, 2CO + O_2 \rightarrow 2CO_2 \\
&5. \, 2C_2H_6 + 7O_2 \rightarrow 4CO_2 + 6H_2O \\
&6. \, C_2H_5OH + 3O_2 \rightarrow 2CO_2 + 3H_2O \\
&7. \, 4FeS_2 + 11O_2 \rightarrow 2Fe_2O_3 + 8SO_2 \\
&8. \, 3P_4 + 10O_3 \rightarrow 6P_2O_5 \\
&9. \, 4NH_3 + 7O_2 \rightarrow 2N_2O_3 + 6H_2O \\
&10. \, 2Si_5H_{11} + 11Br_2 \rightarrow 10Si + 22HBr \\
&11. \, FeCl_3 + 3NaOH \rightarrow Fe(OH)_3 + 3NaCl \\
&12. \, 3Fe + 4H_2O \rightarrow Fe_2O_3 + 4H_2 \\
&13. \, C_{10}H_{22} + 11Cl_2 \rightarrow 10C + 22HCl \\
&14. \, 2FeCl_3 + 3Na_2SO_4 \rightarrow Fe_2(SO_4)_3 + 6NaCl \\
&15. \, 2Al + 6HNO_3 \rightarrow 2Al(NO_3)_3 + 3H_2 \\
&16. \, 2K + 2H_2O \rightarrow 2KOH + H_2 \\
&17. \, 3C_3H_8 + 5S_8 \rightarrow 9CS_2 + 12H_2S \\
&18. \, 2MgCl_2 + 2Al(OH)_3 \rightarrow 2AlCl_3 + 3Mg(OH)_2 \\
&19. \, 2ZnFeS_2 + 5O_2 \rightarrow 2Zn + 2FeO + 4SO_2 \\
&20. \, P_4O_{10} + 6H_2O \rightarrow 4H_3PO_4 \\
&21. \, 4KClO_3 \rightarrow 3KClO_4 + KCl \\
&22. \, Mg_3N_2 + 6H_2O \rightarrow 3Mg(OH)_2 + 2NH_3 \\
\end{aligned}
}