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Reviewed CSCA Chemistry question · Easy

Which of the following equations is correctly balanced for the reaction between iron(III) oxide and carbon monoxide to produce iron and carbon dioxide?

  1. Fe2O3 + 3CO → 2Fe + 3CO2
  2. 2Fe2O3 + 3CO → 4Fe + 3CO2
  3. Fe2O3 + 2CO → 2Fe + 2CO2
  4. Fe2O3 + CO → 2Fe + CO2
Show the answer and explanation

Correct answer

A. Fe2O3 + 3CO → 2Fe + 3CO2

Principle or equation

A balanced chemical equation must have the same number of each type of atom on both sides.

Why this answer is correct

Check each option: In option A, left side has 2 Fe, 3 C, and 6 O; right side has 2 Fe, 3 C, and 6 O. It is balanced. Option B has 4 Fe, 3 C, and 9 O on left but 4 Fe, 3 C, and 6 O on right. Option C has 2 Fe, 2 C, and 5 O on left but 2 Fe, 2 C, and 4 O on right. Option D has 2 Fe, 1 C, and 4 O on left but 2 Fe, 1 C, and 2 O on right.

Example

Balancing Fe2O3 + CO → Fe + CO2: start with Fe2O3, need 2 Fe on right; then balance O by using 3 CO and 3 CO2, giving Fe2O3 + 3CO → 2Fe + 3CO2.

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