8th Grade Chemistry Practice Test PDF

[Document Starts] 8TH GRADE CHEMISTRY PRACTICE TEST (60 QUESTIONS) Name: __________________________________________ Date: _____________________ ------------------------------------------------------------------------ Part I: Multip...

[Document Starts] 8TH GRADE CHEMISTRY PRACTICE TEST (60 QUESTIONS) Name: __________________________________________ Date: _____________________ ------------------------------------------------------------------------ Part I: Multiple Choice (1–20) ------------------------------------------------------------------------ Directions: Select the best answer for each question and clearly mark your choice. 1. Which of the following best describes chemistry? a) The study of living organisms b) The study of matter and its properties c) The study of motion and forces d) The study of Earth’s weather and atmosphere 2. Which statement is true about mass and weight? a) Mass and weight are the same on Earth but different on the Moon b) Mass stays the same, while weight changes with gravity c) Weight stays the same, while mass changes with gravity d) Mass changes when the object is heated, weight does not 3. What are the correct units for mass and weight, respectively? a) Pounds (lb) for mass, grams (g) for weight b) Liters (L) for mass, newtons (N) for weight c) Kilograms (kg) for mass, newtons (N) for weight d) Newtons (N) for mass, kilograms (kg) for weight 4. Which formula correctly represents weight? a) Weight = Mass ÷ Gravity b) Weight = Mass × Gravity c) Weight = Volume × Density d) Weight = Density ÷ Mass 5. When ice melts into liquid water, this process is an example of: a) A chemical change b) A physical change c) An ionic reaction d) Sublimation 6. In which phase change does a liquid become a gas?  a) Freezing b) Condensation c) Evaporation/Boiling d) Deposition 7. Which statement about chemical changes is correct? a) They only occur at very high temperatures b) They never involve a change in appearance c) A new substance is formed with different properties d) They are always visible to the human eye 8. The atomic number of an element is determined by the number of: a) Electrons in the nucleus b) Neutrons in the outer shell c) Protons in the nucleus d) Neutrons plus electrons 9. If an atom has 11 protons, 12 neutrons, and 11 electrons, which statement is true? a) Its mass number is 23 b) Its atomic number is 12 c) It has a net positive charge d) It is an ion with a -1 charge 10. What happens to an atom if it gains an electron? a) It becomes a positively charged ion (cation) b) It becomes a negatively charged ion (anion) c) Its atomic number increases by 1 d) It changes into a different element 11. An isotope of an element differs from another isotope of the same element by the number of: a) Protons b) Electrons c) Neutrons d) Valence electrons 12. Noble gases (like Helium and Neon) are stable because they: a) Have full valence shells b) Are always liquids at room temperature c) Have no protons d) Contain a stable number of ions 13. Which bond involves the transfer of electrons from a metal to a non-metal? a) Covalent bond b) Ionic bond  c) Metallic bond d) Hydrogen bond 14. Which bond involves the sharing of electrons between two non-metals? a) Covalent bond b) Ionic bond c) Metallic bond d) Hydrogen bond 15. What is the correct formula for density? a) Density = Mass + Volume b) Density = Mass ÷ Volume c) Density = Mass × Volume d) Density = Volume ÷ Mass 16. An object has a mass of 50 g and a volume of 10 mL. What is its density? a) 0.2 g/mL b) 5 g/mL c) 40 g/mL d) 500 g/mL 17. Which statement describes a property of surface tension? a) It is caused by electrons jumping between atoms b) It is reduced by strong hydrogen bonding c) It allows some insects to walk on water d) It is caused by metallic bonds in liquids 18. If you have a liquid in a container that has strong surface tension, you might observe: a) A thick foam forming at the top b) The liquid molecules forming a “skin-like” surface c) Rapid evaporation at room temperature d) The container melting under normal conditions 19. What do valence electrons primarily determine? a) The element’s mass number b) The type of chemical reactions an element can undergo c) The rate of radioactivity in an atom d) The number of protons in the nucleus 20. Which of these best defines an element? a) A substance made of two or more types of atoms b) A mixture of compounds and molecules c) A pure substance made of only one type of atom d) A molecule with varying neutron counts ------------------------------------------------------------------------ Part II: True or False (21–40) ------------------------------------------------------------------------ Directions: Write T for true or F for false in the space provided. 21. _____ Matter is defined as anything that has mass and takes up space. 22. _____ Weight remains the same no matter where you are in the universe. 23. _____ Mass is measured in newtons (N). 24. _____ Sublimation is the change from a solid directly to a gas. 25. _____ A physical change creates a completely new substance with different properties. 26. _____ Burning wood is an example of a chemical change. 27. _____ Protons carry a positive charge, whereas electrons carry a negative charge. 28. _____ An ion is formed when the number of neutrons in an atom changes. 29. _____ The atomic number of an element tells us how many protons it has. 30. _____ If an oxygen atom gains two electrons, it becomes negatively charged. 31. _____ Isotopes of an element have the same number of protons but different numbers of neutrons. 32. _____ Noble gases are unstable because their valence shell is not full. 33. _____ A covalent bond occurs when electrons are transferred from one atom to another. 34. _____ An ionic bond typically forms between a metal and a non-metal. 35. _____ Hydrogen bonds are generally weaker than covalent bonds. 36. _____ Valence electrons are located in the innermost shell of an atom. 37. _____ Density can be calculated by dividing an object’s mass by its volume. 38. _____ A substance with a density of 2 g/mL will float on water (density ≈ 1 g/mL). 39. _____ Surface tension in water is a result of hydrogen bonding between water molecules. 40. _____ Melting ice and boiling water are examples of physical changes. ------------------------------------------------------------------------ Part III: Additional Multiple Choice (41–60) ------------------------------------------------------------------------ Directions: Select the best answer for each question. 41. Which state of matter typically has the highest energy level among the four listed? a) Solid b) Liquid c) Gas d) Plasma 42. What occurs during evaporation? a) Particles in a gas lose energy and become a liquid b) Particles at the surface of a liquid gain enough energy to become a gas  c) A solid changes directly to a gas d) A gas changes directly to a solid 43. Which of the following is NOT considered a physical change? a) Tearing paper b) Dissolving sugar in water c) Burning a piece of paper d) Melting wax 44. An element’s atomic mass is best described as the sum of: a) Protons + electrons b) Protons + neutrons c) Electrons + ions d) Neutrons + ions 45. A cation (positively charged ion) is formed when: a) An atom gains electrons b) An atom loses electrons c) An atom gains protons d) A neutron leaves the nucleus 46. If Magnesium (Mg) has 12 protons, 12 neutrons, and 10 electrons, what is its charge? a) +2 b) -2 c) +1 d) -1 47. Which property is NOT typically used to describe or measure matter? a) Mass b) Volume c) Color d) Speed 48. Which is an example of an ionic compound? a) O₂ (oxygen gas) b) NaCl (table salt) c) CO₂ (carbon dioxide) d) H₂O (water) 49. A covalent bond in which electrons are shared equally is called: a) Polar b) Nonpolar c) Metallic d) Hydrogen 50. What must be true for atoms to form a stable ionic bond? a) Each atom must share one electron b) The total charges must balance out c) They must both be metals d) They must both be non-metals 51. In a water molecule (H₂O), the bond between hydrogen and oxygen is an example of: a) Ionic bonding b) Covalent bonding c) Metallic bonding d) No bonding occurs 52. Which subatomic particles are found in the nucleus of an atom? a) Protons and electrons b) Electrons and neutrons c) Protons and neutrons d) Only electrons 53. Which statement correctly describes a CHEMICAL property of a substance? a) Its density is 2.0 g/mL b) It boils at 100°C c) It reacts with acid to form hydrogen gas d) It melts at 0°C 54. When a solid is heated and becomes a liquid, the process is known as: a) Freezing b) Melting c) Deposition d) Sublimation 55. Which scenario describes a physical change? a) Iron rusts when exposed to water and oxygen b) A piece of wood is burned to ash c) Water vapor condenses on a cold window d) Milk turns sour after being left out 56. Atoms bond with each other mainly to: a) Achieve a full valence electron shell b) Decrease their atomic mass c) Change into new elements d) Release neutrons from the nucleus 57. Which of the following best describes the term “isotope”?  a) An atom that has gained or lost electrons b) An atom with the same number of protons but different neutrons c) A compound formed by ionic bonds d) Any negatively charged particle 58. What is typically true about solids compared to liquids and gases? a) Solids have particles with the most energy b) Solids have a definite shape and volume c) Solids can be compressed easily d) Solids always conduct electricity 59. The chemical formula H₂CO₃ describes: a) Water (H₂O) b) Carbonic acid c) Carbon dioxide d) Bicarbonate ion 60. What is the best example of a mixture? a) Helium gas in a balloon (He) b) Sugar (C₁₂H₂₂O₁₁) c) Salt water (NaCl dissolved in H₂O) d) Iron (Fe) ------------------------------------------------------------------------ Answer Key ------------------------------------------------------------------------ [Separate Page / Teacher Use Only] Part I: Multiple Choice (1–20) 1. b 2. b 3. c 4. b 5. b 6. c 7. c 8. c 9. a 10. b 11. c 12. a 13. b 14. a 15. b 16. b 17. c 18. b 19. b 20. c Part II: True or False (21–40) 21. True 22. False 23. False 24. True 25. False 26. True 27. True 28. False 29. True 30. True 31. True 32. False 33. False 34. True 35. True 36. False 37. True 38. False 39. True 40. True Part III: Additional Multiple Choice (41–60) 41. d 42. b 43. c 44. b 45. b 46. a 47. d 48. b 49. b 50. b 51. b 52. c 53. c 54. b 55. c 56. a 57. b 58. b 59. b 60. c [Document Ends]