50 Examples Of Balanced Chemical Equations With Answers Pdf

50 Examples of Balanced Chemical Equations with Answers

This comprehensive guide provides 50 examples of balanced chemical equations, categorized for easy understanding and enhanced learning. Each example includes the reactants, products, and the balanced equation itself. This resource is invaluable for students learning stoichiometry and chemistry fundamentals. While a PDF download isn't directly provided (as per your instructions), this detailed article serves the same purpose, offering a readily accessible and easily printable resource.

Understanding Balanced Chemical Equations

Before diving into the examples, let's refresh our understanding of balanced chemical equations. A chemical equation represents a chemical reaction, showing the reactants (starting materials) transforming into products (resulting substances). Balancing the equation ensures that the number of atoms of each element is the same on both sides, adhering to the law of conservation of mass. This law dictates that matter cannot be created or destroyed in a chemical reaction; it simply changes form.

Key Components of a Balanced Equation

• Reactants: These are the substances that react with each other, written on the left side of the equation.
• Products: These are the substances formed as a result of the reaction, written on the right side of the equation.
• Arrow (→): This symbol separates the reactants from the products, indicating the direction of the reaction.
• Coefficients: These are the numbers placed before chemical formulas to balance the equation. They indicate the relative number of molecules or moles of each substance involved.

50 Balanced Chemical Equations with Answers

The following examples are categorized for clarity. Remember to always check your balanced equation to ensure the number of atoms for each element is equal on both sides.

Combustion Reactions

Combustion reactions involve the rapid reaction of a substance with oxygen, often producing heat and light.

1. CH₄ + 2O₂ → CO₂ + 2H₂O (Methane combustion)
2. C₃H₈ + 5O₂ → 3CO₂ + 4H₂O (Propane combustion)
3. 2C₂H₆ + 7O₂ → 4CO₂ + 6H₂O (Ethane combustion)
4. C₄H₁₀ + 13/2 O₂ → 4CO₂ + 5H₂O (Butane combustion - note the fractional coefficient)
5. 2C₂H₂ + 5O₂ → 4CO₂ + 2H₂O (Acetylene combustion)

Synthesis Reactions (Combination Reactions)

Synthesis reactions involve two or more reactants combining to form a single product.

6. 2Na + Cl₂ → 2NaCl (Sodium chloride synthesis)
7. CaO + H₂O → Ca(OH)₂ (Calcium hydroxide synthesis)
8. SO₂ + H₂O → H₂SO₃ (Sulfurous acid synthesis)
9. N₂ + 3H₂ → 2NH₃ (Ammonia synthesis)
10. Fe + S → FeS (Iron sulfide synthesis)

Decomposition Reactions

Decomposition reactions involve a single reactant breaking down into two or more simpler products.

11. 2H₂O → 2H₂ + O₂ (Water decomposition)
12. 2KClO₃ → 2KCl + 3O₂ (Potassium chlorate decomposition)
13. CaCO₃ → CaO + CO₂ (Calcium carbonate decomposition)
14. 2HgO → 2Hg + O₂ (Mercury(II) oxide decomposition)
15. 2NaHCO₃ → Na₂CO₃ + H₂O + CO₂ (Sodium bicarbonate decomposition)

Single Displacement Reactions (Substitution Reactions)

Single displacement reactions involve one element replacing another in a compound.

16. Zn + 2HCl → ZnCl₂ + H₂ (Zinc reacting with hydrochloric acid)
17. Fe + CuSO₄ → FeSO₄ + Cu (Iron displacing copper)
18. Mg + 2H₂O → Mg(OH)₂ + H₂ (Magnesium reacting with water)
19. 2Al + 6HCl → 2AlCl₃ + 3H₂ (Aluminum reacting with hydrochloric acid)
20. Cu + 2AgNO₃ → Cu(NO₃)₂ + 2Ag (Copper displacing silver)

Double Displacement Reactions (Metathesis Reactions)

Double displacement reactions involve the exchange of ions between two compounds.

21. AgNO₃ + NaCl → AgCl + NaNO₃ (Silver chloride precipitation)
22. BaCl₂ + Na₂SO₄ → BaSO₄ + 2NaCl (Barium sulfate precipitation)
23. Pb(NO₃)₂ + 2KI → PbI₂ + 2KNO₃ (Lead iodide precipitation)
24. HCl + NaOH → NaCl + H₂O (Neutralization reaction)
25. H₂SO₄ + 2KOH → K₂SO₄ + 2H₂O (Neutralization reaction)

Acid-Base Reactions (Neutralization Reactions)

These are a specific type of double displacement reaction where an acid reacts with a base to produce salt and water. Examples 24 and 25 above are also acid-base reactions.

26. HNO₃ + LiOH → LiNO₃ + H₂O (Nitric acid and lithium hydroxide)
27. H₂SO₄ + Ca(OH)₂ → CaSO₄ + 2H₂O (Sulfuric acid and calcium hydroxide)
28. HCl + NH₃ → NH₄Cl (Hydrochloric acid and ammonia)
29. CH₃COOH + NaOH → CH₃COONa + H₂O (Acetic acid and sodium hydroxide)
30. H₃PO₄ + 3NaOH → Na₃PO₄ + 3H₂O (Phosphoric acid and sodium hydroxide)

Redox Reactions (Oxidation-Reduction Reactions)

Redox reactions involve the transfer of electrons between reactants. One substance is oxidized (loses electrons), and another is reduced (gains electrons).

31. 2Mg + O₂ → 2MgO (Magnesium oxidation)
32. 2Fe + 3Cl₂ → 2FeCl₃ (Iron oxidation)
33. Cu + 2H₂SO₄ → CuSO₄ + SO₂ + 2H₂O (Copper oxidation, sulfuric acid reduction)
34. Zn + Cu²⁺ → Zn²⁺ + Cu (Zinc oxidation, copper reduction)
35. MnO₂ + 4HCl → MnCl₂ + Cl₂ + 2H₂O (Manganese dioxide reduction, hydrochloric acid oxidation)

Precipitation Reactions

These are double displacement reactions that result in the formation of a solid precipitate. Examples 21, 22, and 23 above are also precipitation reactions.

36. 2AgNO₃ + K₂CrO₄ → Ag₂CrO₄ + 2KNO₃ (Silver chromate precipitation)
37. Pb(NO₃)₂ + Na₂S → PbS + 2NaNO₃ (Lead sulfide precipitation)
38. FeCl₃ + 3NaOH → Fe(OH)₃ + 3NaCl (Iron(III) hydroxide precipitation)
39. Ba(NO₃)₂ + K₂SO₄ → BaSO₄ + 2KNO₃ (Barium sulfate precipitation - repeated for emphasis)
40. CuSO₄ + 2KOH → Cu(OH)₂ + K₂SO₄ (Copper(II) hydroxide precipitation)

Gas Evolution Reactions

These reactions produce a gas as a product.

41. CaCO₃ + 2HCl → CaCl₂ + H₂O + CO₂ (Calcium carbonate reacting with acid)
42. Na₂S + 2HCl → 2NaCl + H₂S (Hydrogen sulfide gas evolution)
43. NH₄Cl + NaOH → NaCl + H₂O + NH₃ (Ammonia gas evolution)
44. Zn + 2HCl → ZnCl₂ + H₂ (Hydrogen gas evolution - repeated for emphasis)
45. 2KClO₃ → 2KCl + 3O₂ (Oxygen gas evolution - repeated for emphasis)

More Complex Reactions

These examples showcase reactions involving more complex chemical formulas.

46. C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O (Glucose combustion)
47. 2C₂H₅OH + 6O₂ → 4CO₂ + 6H₂O (Ethanol combustion)
48. 2KMnO₄ + 16HCl → 2KCl + 2MnCl₂ + 5Cl₂ + 8H₂O (Potassium permanganate reaction with hydrochloric acid)
49. (NH₄)₂Cr₂O₇ → Cr₂O₃ + N₂ + 4H₂O (Ammonium dichromate decomposition)
50. 3Cu + 8HNO₃ → 3Cu(NO₃)₂ + 2NO + 4H₂O (Copper reaction with nitric acid)

Conclusion

This comprehensive list of 50 balanced chemical equations provides a strong foundation for understanding chemical reactions. Remember to practice balancing equations regularly to improve your skills and grasp the fundamental principles of stoichiometry. This collection covers various reaction types, ensuring a diverse range of practice examples. Consistent practice and a methodical approach will lead to mastery of balancing chemical equations. Further exploration of different reaction types and mechanisms will further enhance your understanding of chemistry. Remember to always check your work to ensure mass balance is achieved.