CHEMISTRY - CHEMICAL EQUATIONS

Balancing Equations Worksheet

  • Focuses on balancing chemical equations using smallest whole-number coefficients
  • Includes reactions involving combustion, oxidation, and synthesis
  • Challenges students with complex multi-step reactions
  • Designed for Grade 9 students with advanced chemistry skills

Here are the first 3 questions. Click “View all questions” to see the complete assessment.

Q1.

The complete combustion of butane is represented by a C4H10 + b O2 → c CO2 + d H2O. Which sequence gives a, b, c and d as the smallest whole-number coefficients?

  1. A) 1, 6, 4, 5
  2. B) 2, 13, 8, 10
  3. C) 4, 13, 16, 20
  4. D) 2, 10, 8, 10

Q2.

Iron pyrite is roasted according to FeS2 + O2 → Fe2O3 + SO2. Which is the correctly balanced equation using the smallest whole-number coefficients?

  1. A) 2 FeS2 + 7 O2 → Fe2O3 + 4 SO2
  2. B) 2 FeS2 + 6 O2 → 2 Fe2O3 + 4 SO2
  3. C) 4 FeS2 + 9 O2 → 2 Fe2O3 + 8 SO2
  4. D) 4 FeS2 + 11 O2 → 2 Fe2O3 + 8 SO2

Q3.

Sodium thiosulfate reacts with hydrochloric acid as shown: Na2S2O3 + HCl → NaCl + SO2 + S + H2O. Which sequence gives the smallest whole-number coefficients in the order shown?

  1. A) 2, 2, 2, 2, 1, 2
  2. B) 1, 2, 1, 2, 1, 1
  3. C) 1, 2, 2, 1, 1, 1
  4. D) 1, 1, 2, 1, 1, 1

Q4.

Calcium nitride reacts with water according to Ca3N2 + H2O → Ca(OH)2 + NH3. Which sequence gives the coefficients of Ca3N2, H2O, Ca(OH)2 and NH3 after balancing?

  1. A) 1, 6, 2, 3
  2. B) 2, 6, 3, 4
  3. C) 1, 6, 3, 2
  4. D) 1, 3, 3, 2

Q5.

Ammonia is oxidised to nitrogen monoxide and water: NH3 + O2 → NO + H2O. Which is the correctly balanced equation?

  1. A) 6 NH3 + 5 O2 → 6 NO + 6 H2O
  2. B) 2 NH3 + 3 O2 → 2 NO + 3 H2O
  3. C) 4 NH3 + 4 O2 → 4 NO + 6 H2O
  4. D) 4 NH3 + 5 O2 → 4 NO + 6 H2O

Q6.

Phosphorus is manufactured using the equation Ca3(PO4)2 + SiO2 + C → P4 + CaSiO3 + CO. Which sequence gives the smallest whole-number coefficients in the order shown?

  1. A) 2, 3, 5, 1, 3, 5
  2. B) 2, 6, 6, 1, 6, 6
  3. C) 2, 6, 10, 1, 6, 10
  4. D) 1, 6, 10, 1, 6, 10

Q7.

In acidic solution, the ionic equation is MnO4− + H+ + Fe2+ → Mn2+ + Fe3+ + H2O. Which sequence gives the smallest whole-number coefficients in the order shown while balancing both atoms and charge?

  1. A) 1, 4, 5, 1, 5, 2
  2. B) 1, 8, 5, 1, 5, 4
  3. C) 1, 8, 4, 1, 4, 4
  4. D) 2, 8, 5, 2, 5, 4

Q8.

Copper reacts with concentrated nitric acid according to Cu + HNO3 → Cu(NO3)2 + NO2 + H2O. Which equation is correctly balanced using the smallest whole-number coefficients?

  1. A) 2 Cu + 4 HNO3 → 2 Cu(NO3)2 + 2 NO2 + 2 H2O
  2. B) Cu + 4 HNO3 → Cu(NO3)2 + NO2 + 2 H2O
  3. C) Cu + 2 HNO3 → Cu(NO3)2 + NO2 + H2O
  4. D) Cu + 4 HNO3 → Cu(NO3)2 + 2 NO2 + 2 H2O

Q9.

The particle models in the figure represent the six substances in reaction A + B → C + D + E + F. Which sequence gives the smallest whole-number coefficients for A, B, C, D, E and F, respectively?

Diagram for question 9: The particle models in the figure represent the six substances in reaction A + B → C + D + E + F. Which…
  1. A) 2, 14, 4, 4, 3, 7
  2. B) 1, 12, 2, 2, 2, 6
  3. C) 1, 14, 2, 2, 3, 7
  4. D) 1, 14, 2, 1, 4, 7

Q10.

The molecular models in the figure show reaction A + B → C + D. Which sequence gives the smallest whole-number coefficients for A, B, C and D, respectively?

Diagram for question 10: The molecular models in the figure show reaction A + B → C + D. Which sequence gives the smallest…
  1. A) 2, 4, 2, 5
  2. B) 1, 5, 1, 5
  3. C) 1, 4, 1, 5
  4. D) 1, 3, 1, 5

What this assessment covers

Concepts tested

  • Balancing chemical equations
  • Combustion reactions
  • Oxidation-reduction reactions
  • Synthesis reactions
  • Stoichiometry in chemical equations

Question Mix

  • Hard questions included

Skills you build

  • Identify correct coefficients for balanced equations
  • Apply stoichiometry to balance reactions
  • Analyze chemical reactions for atom and charge balance
  • Interpret chemical equations from particle models
  • Solve complex chemical balancing problems

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