Practice Example (2.2) - Stoichiometry - IB 10 Sciences (Group 4)

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10 questions

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6 sample questions

Question 1.
Balance the equation: K + Cl₂ → KCl
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Chlorine comes in pairs, so start by writing 2KCl.
Question 2.
Balance the equation: Zn + HCl → ZnCl₂ + H₂
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Zinc chloride contains two chlorine atoms.
3Question 3.
Which equation is correctly balanced?
- 2Mg + O₂ → MgO
- Mg + O₂ → 2MgO
- 2Mg + O₂ → 2MgO
- Mg + 2O₂ → 2MgO
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Count magnesium and oxygen on both sides of each option.
4Question 4.
When C₂H₆ + O₂ → CO₂ + H₂O is balanced with the smallest whole numbers, what is the coefficient of O₂?
- 3
- 5
- 7
- 14
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Balance carbon and hydrogen first, then double to clear the half.
Question 5.
Petrol contains octane, C₈H₁₈. Balance the equation for its complete combustion: C₈H₁₈ + O₂ → CO₂ + H₂O
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Balance carbon and hydrogen, then clear the half by doubling.
Question 6.
Hot iron reacts with steam to form the magnetic oxide Fe₃O₄ and hydrogen gas. Write and balance the equation.
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Balance iron first, then oxygen, and hydrogen last.

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