CHEMISTRY - BALANCING EQUATIONS

Balancing Equations Practice Problems

  • 10 questions
  • Difficulty: Hard
  • Board: CAIE
  • Attempt online on the examination portal

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

Q1.

What are the smallest whole-number coefficients for C4H10 + O2 → CO2 + H2O, in the order shown?

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

Q2.

When FeS2 is roasted in oxygen, the products are Fe2O3 and SO2. Which equation is correctly balanced using the smallest whole-number coefficients?

  1. A) 4FeS2 + 9O2 → 2Fe2O3 + 8SO2
  2. B) 2FeS2 + 7O2 → 2Fe2O3 + 4SO2
  3. C) 4FeS2 + 11O2 → 2Fe2O3 + 8SO2
  4. D) 2FeS2 + 5O2 → Fe2O3 + 4SO2

Q3.

Balance KMnO4 + HCl → KCl + MnCl2 + H2O + Cl2. Which list gives the smallest whole-number coefficients in the order shown?

  1. A) 2, 16, 2, 2, 4, 5
  2. B) 1, 8, 1, 1, 4, 5
  3. C) 2, 16, 2, 2, 8, 5
  4. D) 2, 12, 2, 2, 6, 3

Q4.

Aluminium reacts with sulfuric acid according to Al + H2SO4 → Al2(SO4)3 + H2. Which balanced equation has the smallest whole-number coefficients?

  1. A) 3Al + 2H2SO4 → Al2(SO4)3 + 2H2
  2. B) 2Al + 3H2SO4 → 2Al2(SO4)3 + 3H2
  3. C) 2Al + 3H2SO4 → Al2(SO4)3 + 3H2
  4. D) 2Al + H2SO4 → Al2(SO4)3 + H2

Q5.

For the reaction Na2CO3 + H3PO4 → Na3PO4 + CO2 + H2O, what is the sum of the smallest whole-number coefficients?

  1. A) 11
  2. B) 12
  3. C) 13
  4. D) 15

Q6.

Ammonia is oxidised according to NH3 + O2 → NO + H2O. If the coefficient of NH3 is fixed at 12, what coefficient must be placed before O2?

  1. A) 18
  2. B) 10
  3. C) 12
  4. D) 15

Q7.

Lead(II) nitrate decomposes according to Pb(NO3)2 → PbO + NO2 + O2. Which list gives the smallest whole-number coefficients in the order shown?

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

Q8.

Balance P4 + KOH + H2O → PH3 + KH2PO2. Which list gives the smallest whole-number coefficients in the order shown?

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

Q9.

The figure shows the structural formulae of the substances in a combustion reaction. What are the smallest whole-number coefficients for the four substances, in their left-to-right order?

Diagram for question 9: The figure shows the structural formulae of the substances in a combustion reaction. What are the smallest…
  1. A) 2, 7, 6, 6
  2. B) 1, 7, 3, 3
  3. C) 2, 5, 6, 6
  4. D) 1, 3, 3, 3

Q10.

The figure shows an unbalanced reaction with empty coefficient boxes. Which list gives the smallest whole-number coefficients for the substances in their left-to-right order?

Diagram for question 10: The figure shows an unbalanced reaction with empty coefficient boxes. Which list gives the smallest…
  1. A) 10, 6, 3, 10
  2. B) 5, 3, 3, 5
  3. C) 6, 5, 3, 6
  4. D) 10, 3, 6, 10

What this assessment covers

Concepts Tested

  • balancing equations

Question Mix

  • Hard questions included

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