Grade 10 Chemistry Questions and Answers
A free sample of Grade 10 Chemistry practice questions with the correct answer and an explanation, following the Lebanese curriculum. Useful for revision before school tests.
أسئلة الكيمياء للصف 10 مع الأجوبة والشرح وفق المنهج اللبناني.
How to use this page: read each question, try to answer it yourself, then open the answer to check your reasoning. Questions are grouped by the chapter they belong to on EduRise, in the order of the Lebanese Grade 10 Chemistry programme.
12 Grade 10 Chemistry practice questions
Chapter: Structure of the Atom · easy
1. What is the electron distribution of the fluorine atom (Z = 9)?
- A. (K)²(L)⁷
- B. (K)²(L)⁶
- C. (K)⁸(L)¹
- D. (K)²(L)⁸
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Answer: (K)²(L)⁷
Explanation: 9 electrons: K takes 2, L takes 7 → (K)²(L)⁷.
Chapter: Structure of the Atom · easy
2. An atom has the electron distribution (K)²(L)⁷. Which element is it?
- A. nitrogen (Z = 7)
- B. fluorine (Z = 9)
- C. neon (Z = 10)
- D. oxygen (Z = 8)
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Answer: fluorine (Z = 9)
Explanation: Number of electrons = 2 + 7 = 9 = Z, so the element is fluorine.
Chapter: The Molecule · easy
3. How many covalent bonds does nitrogen (Z = 7) form in a molecule, following the duet/octet rule?
- A. 4
- B. 1
- C. 5
- D. 3
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Answer: 3
Explanation: (K)²(L)⁵: 5 valence electrons; 8 − 5 = 3 electrons are missing to reach the octet, so it forms 3 bonds.
Chapter: The Molecule · easy
4. In the molecule CH₂O, which bond links C and O?
- A. a single covalent bond
- B. a triple covalent bond
- C. a double covalent bond
- D. an ionic bond
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Answer: a double covalent bond
Explanation: Structural formula H₂C=O: 2 shared pairs between C and O so that every atom reaches its octet (H its duet).
Chapter: The Ion · easy
5. What is the formula of the ammonium ion?
- A. NH₄²⁺
- B. NH₄⁺
- C. NH₃⁺
- D. NH₄⁻
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Answer: NH₄⁺
Explanation: The ammonium ion is NH₄⁺; its charge belongs to the whole group.
Chapter: The Ion · easy
6. Adding sodium hydroxide solution to a solution gives a blue precipitate. Which ion does the solution contain?
- A. Cu²⁺
- B. Zn²⁺
- C. Al³⁺
- D. Cl⁻
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Answer: Cu²⁺
Explanation: Sodium hydroxide solution gives a blue precipitate with Cu²⁺ ions.
Chapter: Quantity of Matter - Concentration of a Solution · easy
7. How do you read the volume of an aqueous solution in a pipette or flask?
- A. looking from above the mark
- B. at the top of the meniscus
- C. at the bottom of the meniscus, looking from below
- D. eye level with the mark, at the bottom of the meniscus
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Answer: eye level with the mark, at the bottom of the meniscus
Explanation: Reading must be done at eye level, with the bottom of the meniscus tangent to the mark (no parallax error).
Chapter: Quantity of Matter - Concentration of a Solution · easy
8. On a label, "purity 37 %" for hydrochloric acid means:
- A. 1 L of solution contains 37 g of HCl
- B. 100 g of the solution contain 37 g of HCl
- C. 37 mL of HCl in 100 mL
- D. the concentration is 37 mol/L
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Answer: 100 g of the solution contain 37 g of HCl
Explanation: Purity (mass percentage) = mass of HCl / mass of solution × 100.
Chapter: Chemical Transformation · easy
9. Find the coefficient a that balances the equation of the combustion of ethanol: C₂H₅OH + 3 O₂ → a CO₂ + 3 H₂O
- A. 3
- B. 2
- C. 1
- D. 4
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Answer: 2
Explanation: With a = 2: C₂H₅OH + 3 O₂ → 2 CO₂ + 3 H₂O. Count the atoms on each side — C: 2 = 2; H: 6 = 6; O: 7 = 7 ✓.
Chapter: Chemical Transformation · easy
10. Find the coefficient a that balances the equation of the oxidation of sulfur dioxide: 2 SO₂ + O₂ → a SO₃
- A. 3
- B. 4
- C. 1
- D. 2
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Answer: 2
Explanation: With a = 2: 2 SO₂ + O₂ → 2 SO₃. Count the atoms on each side — S: 2 = 2; O: 6 = 6 ✓.
Chapter: Acid-base Reactions · easy
11. The acid found in vinegar is:
- A. nitric acid HNO₃
- B. hydrochloric acid HCl
- C. acetic acid CH₃COOH
- D. sulfuric acid H₂SO₄
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Answer: acetic acid CH₃COOH
Explanation: Vinegar is a dilute solution of acetic (ethanoic) acid CH₃COOH.
Chapter: Acid-base Reactions · easy
12. What amount of H₃O⁺ ions is contained in 100 mL of hydrochloric acid solution at 0.080 mol/L?
- A. 0.00800 mol
- B. 1.25 mol
- C. 8.00 mol
- D. 0.800 mol
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Answer: 0.00800 mol
Explanation: n = C × V = 0.080 × 0.1 L = 0.00800 mol (convert 100 mL = 0.1 L).
More practice
These are sample questions only. The full Grade 10 Chemistry course on EduRise includes every chapter, lessons, 742 questions and timed exams.
Chemistry questions in other grades
Other Grade 10 subjects
See also: Grade 10 Chemistry chapters · All question pages · Study guides
About these questions
Where do these Grade 10 Chemistry questions come from?
They are a sample from EduRise's Grade 10 Chemistry question bank (742 questions across 6 chapters), written to follow the Lebanese curriculum. Each chapter on EduRise has its own practice set and a timed exam.
Are the answers explained?
Yes. Every question on EduRise shows the correct answer and an explanation after you answer, in practice mode and in the exam review.
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