Balancing Chemical Equations Quiz
Questions: 16 · 10 minutes
1. Aluminum reacts with hydrochloric acid according to Al + HCl → AlCl₃ + H₂. Which coefficient set balances the equation?
1, 3, 1, 3
2, 6, 2, 3
2, 3, 2, 3
2, 6, 1, 3
2. Propane burns according to C₃H₈ + O₂ → CO₂ + H₂O. Which coefficient set balances the equation in the order shown?
1, 4, 3, 4
2, 7, 6, 8
1, 5, 3, 4
1, 5, 4, 3
3. Potassium chlorate decomposes as KClO₃ → KCl + O₂. What are the smallest whole-number coefficients?
1, 1, 3
2, 1, 3
3, 3, 2
2, 2, 3
4. Calcium hydroxide and phosphoric acid react as Ca(OH)₂ + H₃PO₄ → Ca₃(PO₄)₂ + H₂O. Which coefficients balance the equation?
3, 1, 1, 3
2, 3, 1, 6
3, 2, 1, 6
1, 2, 1, 4
5. Using the smallest whole-number coefficients, how is H₂ + O₂ → H₂O balanced?
H₂ + O₂ → H₂O₂
2H₂ + O₂ → 2H₂O
H₂ + 2O₂ → 2H₂O
2H₂ + 2O₂ → 2H₂O
6. Ammonia reacts with oxygen as NH₃ + O₂ → NO + H₂O. What are the smallest whole-number coefficients?
2, 3, 2, 3
4, 5, 4, 6
4, 3, 4, 6
2, 5, 2, 3
7. A student tries to balance H₂ + O₂ → H₂O by changing the product formula to H₂O₂. What should the student do instead?
Add an extra element to whichever side has fewer atoms
Change subscripts whenever an element count is uneven
Keep every chemical formula unchanged and adjust only coefficients
Balance oxygen only because it appears in more than one molecule
8. For Na₃PO₄ + MgCl₂ → Mg₃(PO₄)₂ + NaCl, which coefficients balance the equation in the order shown?
2, 3, 1, 6
1, 3, 1, 3
3, 2, 1, 6
2, 1, 1, 3
9. Silver nitrate reacts with calcium chloride: AgNO₃ + CaCl₂ → AgCl + Ca(NO₃)₂. Which coefficient set balances the equation?
1, 1, 2, 1
2, 2, 2, 1
2, 1, 1, 2
2, 1, 2, 1
10. When counting atoms in 3Ca(OH)₂, how many atoms of calcium, oxygen, and hydrogen are represented, respectively?
3 calcium, 6 oxygen, and 6 hydrogen
3 calcium, 3 oxygen, and 6 hydrogen
6 calcium, 3 oxygen, and 6 hydrogen
3 calcium, 6 oxygen, and 2 hydrogen
11. Which coefficient set balances N₂ + H₂ → NH₃, in the order shown?
1, 2, 2
2, 3, 2
1, 3, 2
2, 1, 2
12. Using the smallest whole-number coefficients, which equation correctly represents iron reacting with oxygen to form Fe₂O₃?
2Fe + O₂ → Fe₂O₃
2Fe + 3O₂ → 2Fe₂O₃
4Fe + 2O₂ → 2Fe₂O₃
4Fe + 3O₂ → 2Fe₂O₃
13. Ethane undergoes combustion: C₂H₆ + O₂ → CO₂ + H₂O. Which coefficient set balances the equation?
1, 3, 2, 3
2, 7, 4, 6
2, 7, 2, 6
2, 5, 4, 6
14. Lead(II) nitrate reacts with potassium iodide: Pb(NO₃)₂ + KI → PbI₂ + KNO₃. Which coefficient set balances the equation?
2, 1, 2, 1
1, 1, 1, 2
1, 2, 2, 1
1, 2, 1, 2
15. In 2Al + 3CuSO₄ → Al₂(SO₄)₃ + 3Cu, what is the coefficient ratio of Al to CuSO₄?
2:3
1:3
2:1
3:2
16. Which equation is already balanced using the smallest whole-number coefficients?
2K + 2H₂O → 2KOH + H₂
Mg + O₂ → MgO
2Na + Cl₂ → NaCl
N₂ + H₂ → 2NH₃