Grade 8 Chemistry Questions and Answers
A free sample of Grade 8 Chemistry practice questions with the correct answer and an explanation, following the Lebanese curriculum. Useful for revision before school tests.
أسئلة الكيمياء للصف 8 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 8 Chemistry programme.
15 Grade 8 Chemistry practice questions
Chapter: Pure Substances · easy
1. What is the meaning of "distilled water"?
- A. a substance made of one kind of chemical entity only, with fixed physical constants
- B. matter containing two or more different substances
- C. pure water obtained by distillation, containing no dissolved salts
- D. a separation method: the mixture is boiled and the vapour is condensed to give a pure liquid
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Answer: pure water obtained by distillation, containing no dissolved salts
Explanation: Distilled water: pure water obtained by distillation, containing no dissolved salts
Chapter: Pure Substances · easy
2. Which term matches this definition: "a graph of the temperature of a substance against time while it is heated"?
- A. boiling point
- B. compound
- C. heating curve
- D. physical property
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Answer: heating curve
Explanation: Heating curve: a graph of the temperature of a substance against time while it is heated
Chapter: Chemical Entities: Atoms and Molecules · easy
3. What is the meaning of "chemical symbol"?
- A. a kind of atom, identified by its name and symbol
- B. the small number written after a symbol that counts the atoms of that element in the molecule
- C. a representation of a molecule with coloured balls for the atoms
- D. one or two letters representing an element (H, O, Cl, Fe)
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Answer: one or two letters representing an element (H, O, Cl, Fe)
Explanation: Chemical symbol: one or two letters representing an element (H, O, Cl, Fe)
Chapter: Chemical Entities: Atoms and Molecules · easy
4. Which term matches this definition: "the number written in front of a formula that counts molecules"?
- A. chemical symbol
- B. coefficient
- C. atom
- D. chemical element
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Answer: coefficient
Explanation: Coefficient: the number written in front of a formula that counts molecules
Chapter: Chemical Entity: Ions · easy
5. Which term matches this definition: "the polyatomic cation NH₄⁺"?
- A. ammonium ion
- B. anion
- C. precipitate
- D. cation
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Answer: ammonium ion
Explanation: Ammonium ion: the polyatomic cation NH₄⁺
Chapter: Chemical Entity: Ions · easy
6. Which term matches this definition: "a neutral solid made of cations and anions arranged in a regular network"?
- A. silver nitrate test
- B. cation
- C. hydroxide ion
- D. ionic compound
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Answer: ionic compound
Explanation: Ionic compound: a neutral solid made of cations and anions arranged in a regular network
Chapter: Chemical Transformations · easy
7. Which term matches this definition: "the principle that atoms are only rearranged, never created or destroyed, in a reaction"?
- A. conservation of mass
- B. exothermic reaction
- C. coefficient
- D. conservation of atoms
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Answer: conservation of atoms
Explanation: Conservation of atoms: the principle that atoms are only rearranged, never created or destroyed, in a reaction
Chapter: Chemical Transformations · easy
8. 8 g of dihydrogen react completely with 24 g of dioxygen. Mass of water formed?
- A. 192
- B. 32
- C. 8
- D. 16
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Answer: 32
Explanation: Conservation of mass: 8 + 24 = 32 g.
Chapter: Types of Chemical Reactions · easy
9. Which term matches this definition: "a reaction in which two compounds exchange their ions"?
- A. activity series
- B. double replacement reaction
- C. electrolysis
- D. synthesis reaction
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Answer: double replacement reaction
Explanation: Double replacement reaction: a reaction in which two compounds exchange their ions
Chapter: Types of Chemical Reactions · easy
10. What is the meaning of "thermal decomposition"?
- A. the reaction of an acid with a base giving a salt and water
- B. the reaction of a fuel with dioxygen releasing heat and light
- C. a decomposition caused by heating
- D. the reaction of a reactive metal with an acid that releases dihydrogen gas
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Answer: a decomposition caused by heating
Explanation: Thermal decomposition: a decomposition caused by heating
Chapter: Rate of a Chemical Reaction · easy
11. Which term matches this definition: "a graph of the volume of gas produced against time, used to follow a reaction"?
- A. state of division
- B. fair test
- C. volume–time curve
- D. manganese dioxide
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Answer: volume–time curve
Explanation: Volume–time curve: a graph of the volume of gas produced against time, used to follow a reaction
Chapter: Rate of a Chemical Reaction · easy
12. What is a catalyst?
- A. a product of the reaction
- B. a substance that stops the reaction
- C. a reactant that is used up
- D. a substance that speeds up a reaction without being consumed
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Answer: a substance that speeds up a reaction without being consumed
Explanation: It is recovered unchanged at the end.
Chapter: Acids and Bases · easy
13. Which is more acidic: drain cleaner (sodium hydroxide) (pH 14) or milk (pH 6.5)?
- A. both are equally acidic
- B. drain cleaner (sodium hydroxide)
- C. neither is acidic
- D. milk
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Answer: milk
Explanation: The lower the pH, the more acidic.
Chapter: Acids and Bases · easy
14. Which term matches this definition: "the OH⁻ ion responsible for basic properties"?
- A. litmus
- B. corrosive
- C. pH
- D. hydroxide ion
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Answer: hydroxide ion
Explanation: Hydroxide ion: the OH⁻ ion responsible for basic properties
Chapter: Salts · easy
15. What is the meaning of "insoluble salt"?
- A. the reaction of an acid with a base giving a salt and water
- B. sodium hydrogen carbonate NaHCO₃, a salt used in baking and as an antacid
- C. a salt that does not dissolve in water, such as calcium carbonate or silver chloride
- D. a shallow basin where sea water evaporates under the sun to leave salt
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Answer: a salt that does not dissolve in water, such as calcium carbonate or silver chloride
Explanation: Insoluble salt: a salt that does not dissolve in water, such as calcium carbonate or silver chloride
More practice
These are sample questions only. The full Grade 8 Chemistry course on EduRise includes every chapter, lessons, 1,144 questions and timed exams.
Chemistry questions in other grades
Other Grade 8 subjects
See also: Grade 8 Chemistry chapters · All question pages · Study guides
About these questions
Where do these Grade 8 Chemistry questions come from?
They are a sample from EduRise's Grade 8 Chemistry question bank (1,144 questions across 11 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.
How do I get the full question bank?
Register at edurise.me and subscribe ($10/month) to practise every chapter of Grade 8 Chemistry, take the timed exams and track your progress.
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