Balancing Chemical Equations Worksheet for 9th - 12th Grade ... - Free Printable

Here are the balanced chemical equations for the homework problems. I have checked each one to make sure the number of atoms for every element is the same on both sides.

1) N₂ + 3 H₂ → 2 NH₃
*(Nitrogen: 2 on left, 2 on right. Hydrogen: 6 on left, 6 on right.)*

2) 2 KClO₃ → 2 KCl + 3 O₂
*(Potassium: 2 on left, 2 on right. Chlorine: 2 on left, 2 on right. Oxygen: 6 on left, 6 on right.)*

3) 2 NaF + Br₂ → 2 NaBr + F₂
*(Sodium: 2 on left, 2 on right. Fluorine: 2 on left, 2 on right. Bromine: 2 on left, 2 on right.)*

4) H₂SO₄ + Mg(OH)₂ → MgSO₄ + 2 H₂O
*(Hydrogen: 4 on left, 4 on right. Sulfur: 1 on left, 1 on right. Oxygen: 6 on left, 6 on right. Magnesium: 1 on left, 1 on right.)*

5) 2 AgNO₃ + MgCl₂ → 2 AgCl + Mg(NO₃)₂
*(Silver: 2 on left, 2 on right. Nitrate group: 2 on left, 2 on right. Magnesium: 1 on left, 1 on right. Chlorine: 2 on left, 2 on right.)*

6) AlBr₃ + K₂SO₄ → No Reaction (or complex double displacement)
*Note: In standard introductory chemistry, Aluminum Sulfate and Potassium Bromide would form, but balancing simple double replacement here usually implies:*
2 AlBr₃ + 3 K₂SO₄ → Al₂(SO₄)₃ + 6 KBr
*(Aluminum: 2 on left, 2 on right. Bromine: 6 on left, 6 on right. Potassium: 6 on left, 6 on right. Sulfate: 3 on left, 3 on right.)*

7) CH₄ + 2 O₂ → CO₂ + 2 H₂O
*(Carbon: 1 on left, 1 on right. Hydrogen: 4 on left, 4 on right. Oxygen: 4 on left, 4 on right.)*

8) C₃H₈ + 5 O₂ → 3 CO₂ + 4 H₂O
*(Carbon: 3 on left, 3 on right. Hydrogen: 8 on left, 8 on right. Oxygen: 10 on left, 10 on right.)*

9) C₈H₁₈ + 12.5 O₂ → 8 CO₂ + 9 H₂O
*Usually written with whole numbers by multiplying by 2:*
2 C₈H₁₈ + 25 O₂ → 16 CO₂ + 18 H₂O

10) FeCl₃ + 3 NaOH → Fe(OH)₃ + 3 NaCl
*(Iron: 1 on left, 1 on right. Chlorine: 3 on left, 3 on right. Sodium: 3 on left, 3 on right. Hydroxide: 3 on left, 3 on right.)*

11) P₄ + 5 O₂ → P₄O₁₀
*(Phosphorus: 4 on left, 4 on right. Oxygen: 10 on left, 10 on right.)*

12) 2 Na + 2 H₂O → 2 NaOH + H₂
*(Sodium: 2 on left, 2 on right. Hydrogen: 4 on left, 4 on right. Oxygen: 2 on left, 2 on right.)*

13) Ag₂O → 2 Ag + ½ O₂
*Usually written with whole numbers:*
2 Ag₂O → 4 Ag + O₂

14) S₈ + 8 O₂ → 8 SO₂
*(Sulfur: 8 on left, 8 on right. Oxygen: 16 on left, 16 on right.)*

15) CO₂ + H₂O → H₂CO₃
*(Already balanced. Carbon: 1, Oxygen: 3, Hydrogen: 2 on both sides.)*

16) 2 K + Br₂ → 2 KBr
*(Potassium: 2 on left, 2 on right. Bromine: 2 on left, 2 on right.)*

17) Cu + 2 AgNO₃ → Cu(NO₃)₂ + 2 Ag
*(Copper: 1 on left, 1 on right. Silver: 2 on left, 2 on right. Nitrate: 2 on left, 2 on right.)*

18) 2 HNO₃ + Na₂CO₃ → 2 NaNO₃ + H₂O + CO₂
*(Hydrogen: 2 on left, 2 on right. Nitrate: 2 on left, 2 on right. Sodium: 2 on left, 2 on right. Carbon: 1 on left, 1 on right. Oxygen in carbonate/water/CO2 balances out.)*

19) H₂O₂ → H₂O + ½ O₂
*Usually written with whole numbers:*
2 H₂O₂ → 2 H₂O + O₂

20) 2 NaBr + CaF₂ → 2 NaF + CaBr₂
*(Sodium: 2 on left, 2 on right. Bromine: 2 on left, 2 on right. Calcium: 1 on left, 1 on right. Fluorine: 2 on left, 2 on right.)*

Final Answer:
1) N₂ + 3 H₂ → 2 NH₃
2) 2 KClO₃ → 2 KCl + 3 O₂
3) 2 NaF + Br₂ → 2 NaBr + F₂
4) H₂SO₄ + Mg(OH)₂ → MgSO₄ + 2 H₂O
5) 2 AgNO₃ + MgCl₂ → 2 AgCl + Mg(NO₃)₂
6) 2 AlBr₃ + 3 K₂SO₄ → Al₂(SO₄)₃ + 6 KBr
7) CH₄ + 2 O₂ → CO₂ + 2 H₂O
8) C₃H₈ + 5 O₂ → 3 CO₂ + 4 H₂O
9) 2 C₈H₁ + 25 O₂ → 16 CO₂ + 18 H₂O
10) FeCl₃ + 3 NaOH → Fe(OH)₃ + 3 NaCl
11) P₄ + 5 O₂ → P₄O₁₀
12) 2 Na + 2 H₂O → 2 NaOH + H₂
13) 2 Ag₂O → 4 Ag + O₂
14) S₈ + 8 O₂ → 8 SO₂
15) CO₂ + H₂O → H₂CO₃
16) 2 K + Br₂ → 2 KBr
17) Cu + 2 AgNO₃ → Cu(NO₃)₂ + 2 Ag
18) 2 HNO₃ + Na₂CO₃ → 2 NaNO₃ + H₂O + CO₂
19) 2 H₂O₂ → 2 H₂O + O₂
20) 2 NaBr + CaF₂ → 2 NaF + CaBr₂