Grade 8 Balancing Chemical Equations Worksheets 2024 - Free Printable

Here are the solutions to your chemistry worksheet. I have balanced each equation and identified the type of reaction for you.

Part 1: Balancing Chemical Equations

To balance these, we make sure the number of atoms for each element is the same on both the left (reactants) and right (products) sides.

1. 1 Zn (s) + 2 AgNO₃ (aq) → 1 Zn(NO₃)₂ (aq) + 2 Ag (s)
2. 1 N₂ (g) + 3 H₂ (g) → 2 NH₃ (g)
3. 1 NaCl (aq) + 1 AgC₂H₃O₂ (aq) → 1 NaC₂H₃O₂ (aq) + 1 AgCl (s)
4. 3 Mg(OH)₂ (aq) + 2 H₃PO₄ (aq) → 6 H₂O (l) + 1 Mg₃(PO₄)₂ (aq)
5. 2 HNO₃ (aq) + 1 Ni (s) → 1 Ni(NO₃)₂ (aq) + 1 H₂ (g)
6. 1 Ba(HCO₃)₂ (s) → 1 BaCO₃ (s) + 1 H₂O (g) + 1 CO₂ (g)
7. 1 BaCl₂ (aq) + 1 Na₂SO₄ (aq) → 2 NaCl (aq) + 1 BaSO₄ (s)
8. 1 Al₂(CO₃)₃ (s) → 1 Al₂O₃ (s) + 3 CO₂ (g)
9. 1 Ca (s) + 2 H₂O (l) → 1 Ca(OH)₂ (aq) + 1 H₂ (g)
10. 2 LiHCO₃ (s) → 1 Li₂CO₃ (s) + 1 H₂O (g) + 1 CO₂ (g)
11. 2 N₂ (g) + 5 O₂ (g) → 2 N₂O₅ (g)
12. 1 MgBr₂ (aq) + 2 KOH (aq) → 2 KBr (aq) + 1 Mg(OH)₂ (s)
13. 1 Mn (s) + 2 CuCl (aq) → 2 Cu (s) + 1 MnCl₂ (s)
*(Note: We assume Cu is +1 here because there is only one Cl)*
14. 8 Zn (s) + 1 S₈ (s) → 8 ZnS (s)
15. 2 NaOH (aq) + 1 H₂SO₄ (aq) → 2 H₂O (l) + 1 Na₂SO₄ (aq)
16. 2 K (s) + 2 H₂O (l) → 2 KOH (aq) + 1 H₂ (g)
17. 1 C₅H₁₂ (l) + 8 O₂ (g) → 6 H₂O (g) + 5 CO₂ (g)
18. 2 KOH (aq) + 1 H₂CO₃ (aq) → 2 H₂O (l) + 1 K₂CO₃ (aq)
19. 1 C₄H₈O₂ (l) + 5 O₂ (g) → 4 H₂O (g) + 4 CO₂ (g)
20. 16 Al (s) + 3 S₈ (s) → 8 Al₂S₃ (s)

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Part 2: Types of Reaction

Here are the 5 main types of reactions usually taught in class, along with their general formulas:

6. Synthesis (or Combination): Two things combine to make one new thing. ($A + B \rightarrow AB$)
7. Decomposition: One big thing breaks apart into smaller pieces. ($AB \rightarrow A + B$)
8. Single Replacement: One element swaps places with another in a compound. ($A + BC \rightarrow AC + B$)
9. Double Replacement: Two compounds swap partners. ($AB + CD \rightarrow AD + CB$)
10. Combustion: Something burns using Oxygen ($O_2$) to create energy, usually making $CO_2$ and $H_2O$.

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Part 3: Identifying the Reaction Types

Here is which type applies to each of the 20 equations above:

1. Single Replacement (Zinc replaces Silver)
2. Synthesis (Nitrogen and Hydrogen combine)
3. Double Replacement (Sodium and Silver swap partners)
4. Double Replacement (Acid-Base neutralization)
5. Single Replacement (Nickel replaces Hydrogen)
6. Decomposition (One compound breaks into three)
7. Double Replacement (Barium and Sodium swap partners)
8. Decomposition (Carbonate breaks down)
9. Single Replacement (Calcium replaces Hydrogen)
10. Decomposition (Bicarbonate breaks down)
11. Synthesis (Nitrogen and Oxygen combine)
12. Double Replacement (Magnesium and Potassium swap partners)
13. Single Replacement (Manganese replaces Copper)
14. Synthesis (Zinc and Sulfur combine)
15. Double Replacement (Acid-Base neutralization)
16. Single Replacement (Potassium replaces Hydrogen)
17. Combustion (Hydrocarbon reacts with Oxygen)
18. Double Replacement (Acid-Base neutralization)
19. Combustion (Organic compound reacts with Oxygen)
20. Synthesis (Aluminum and Sulfur combine)

Final Answer:
See the detailed lists above for the balanced coefficients and reaction types.