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Chemical and Physical Changes Practice Tests

These Grade 7 Science practice tests build understanding of physical and chemical properties, states of matter, particle motion, evidence of reactions, conservation of mass, and energy changes.

Skills covered

  • Distinguishing physical properties from chemical properties
  • Classifying melting, dissolving, cutting, burning, rusting, and reactions as physical or chemical changes
  • Using the particle model to explain states of matter and changes of state
  • Identifying reactants, products, evidence of chemical reactions, and conservation of atoms
  • Explaining exothermic and endothermic energy changes in matter systems

How to use these practice tests

For each question, ask whether the original substance keeps its chemical identity. Then use particle motion, reaction evidence, mass measurements, and energy observations to choose the best-supported answer.

For more Grade 7 Science practice, return to the Grade 7 Science category.

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Grade 7 Chemical and Physical Changes Practice Tests

Practice Grade 7 Science questions about physical properties, chemical properties, matter changes, reactions, conservation of mass, and energy.

Choose the best answer for each question. Review the explanation after submitting your answers.

10 Questions
0/10 Questions0 %
Correct 0
Incorrect 0
Unanswered 10
1. QuestionMultiple choice

What does the law of conservation of mass state?

Please select an answer first.

Correct answer: A

The correct answer is Mass is not created or destroyed in a closed system..

  1. Identify the matter change: Decide whether the substance keeps the same chemical identity or forms one or more new substances.
  2. Use the evidence: The atoms in a closed system are rearranged, so the total mass before and after a reaction remains equal.
  3. Check the particle model: A physical change rearranges or separates particles, while a chemical change creates new particle arrangements and substances.

The atoms in a closed system are rearranged, so the total mass before and after a reaction remains equal.

2. QuestionMultiple choice

Why should a sealed container be used when measuring mass during a gas-producing reaction?

Please select an answer first.

Correct answer: B

The correct answer is It keeps the gas in the system so the measured mass includes all products..

  1. Identify the matter change: Decide whether the substance keeps the same chemical identity or forms one or more new substances.
  2. Use the evidence: If gas escapes from an open container, the measured mass can appear to decrease even though mass is conserved.
  3. Check the particle model: A physical change rearranges or separates particles, while a chemical change creates new particle arrangements and substances.

If gas escapes from an open container, the measured mass can appear to decrease even though mass is conserved.

3. QuestionMultiple choice

A reaction begins with 20 grams of reactants in a closed container. What is the total mass of products?

Please select an answer first.

Correct answer: C

The correct answer is 20 grams.

  1. Identify the matter change: Decide whether the substance keeps the same chemical identity or forms one or more new substances.
  2. Use the evidence: Conservation of mass means the total product mass equals the total reactant mass in a closed system.
  3. Check the particle model: A physical change rearranges or separates particles, while a chemical change creates new particle arrangements and substances.

Conservation of mass means the total product mass equals the total reactant mass in a closed system.

4. QuestionMultiple choice

If a gas escapes from an open flask during a reaction, what may a balance show?

Please select an answer first.

Correct answer: D

The correct answer is The measured mass may decrease because some product left the system..

  1. Identify the matter change: Decide whether the substance keeps the same chemical identity or forms one or more new substances.
  2. Use the evidence: The balance measures only the matter remaining in the open flask, not the gas that escaped.
  3. Check the particle model: A physical change rearranges or separates particles, while a chemical change creates new particle arrangements and substances.

The balance measures only the matter remaining in the open flask, not the gas that escaped.

5. QuestionMultiple choice

Why must chemical equations be balanced?

Please select an answer first.

Correct answer: A

The correct answer is The same number of each type of atom must appear before and after the reaction..

  1. Identify the matter change: Decide whether the substance keeps the same chemical identity or forms one or more new substances.
  2. Use the evidence: Balancing represents conservation of atoms and mass during the reaction.
  3. Check the particle model: A physical change rearranges or separates particles, while a chemical change creates new particle arrangements and substances.

Balancing represents conservation of atoms and mass during the reaction.

6. QuestionMultiple choice

What does a coefficient in a chemical equation show?

Please select an answer first.

Correct answer: B

The correct answer is The number of particles or units of a substance involved.

  1. Identify the matter change: Decide whether the substance keeps the same chemical identity or forms one or more new substances.
  2. Use the evidence: Coefficients indicate how many molecules, formula units, or moles participate in the balanced reaction.
  3. Check the particle model: A physical change rearranges or separates particles, while a chemical change creates new particle arrangements and substances.

Coefficients indicate how many molecules, formula units, or moles participate in the balanced reaction.

7. QuestionMultiple choice

What does a subscript in a chemical formula show?

Please select an answer first.

Correct answer: C

The correct answer is The number of atoms of an element in one particle of the substance.

  1. Identify the matter change: Decide whether the substance keeps the same chemical identity or forms one or more new substances.
  2. Use the evidence: A subscript is part of the formula and identifies how many atoms of that element are in one unit.
  3. Check the particle model: A physical change rearranges or separates particles, while a chemical change creates new particle arrangements and substances.

A subscript is part of the formula and identifies how many atoms of that element are in one unit.

8. QuestionMultiple choice

Which statement about atoms during a chemical reaction is correct?

Please select an answer first.

Correct answer: D

The correct answer is The types and numbers of atoms are conserved, even though their bonds change..

  1. Identify the matter change: Decide whether the substance keeps the same chemical identity or forms one or more new substances.
  2. Use the evidence: Chemical reactions rearrange existing atoms into new substances rather than creating or destroying atoms.
  3. Check the particle model: A physical change rearranges or separates particles, while a chemical change creates new particle arrangements and substances.

Chemical reactions rearrange existing atoms into new substances rather than creating or destroying atoms.

9. QuestionMultiple choice

Why can a reaction seem to lose mass in an open container?

Please select an answer first.

Correct answer: A

The correct answer is A gas product may leave the container and is no longer included in the measurement..

  1. Identify the matter change: Decide whether the substance keeps the same chemical identity or forms one or more new substances.
  2. Use the evidence: The apparent loss comes from an open system, not from violation of conservation of mass.
  3. Check the particle model: A physical change rearranges or separates particles, while a chemical change creates new particle arrangements and substances.

The apparent loss comes from an open system, not from violation of conservation of mass.

10. QuestionMultiple choice

What is a closed system in a matter investigation?

Please select an answer first.

Correct answer: B

The correct answer is A system in which matter does not enter or leave during the observation..

  1. Identify the matter change: Decide whether the substance keeps the same chemical identity or forms one or more new substances.
  2. Use the evidence: A closed system allows energy transfer in some cases but keeps matter inside for accurate mass comparisons.
  3. Check the particle model: A physical change rearranges or separates particles, while a chemical change creates new particle arrangements and substances.

A closed system allows energy transfer in some cases but keeps matter inside for accurate mass comparisons.

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