Explain Matter is Conserved - 5th Grade Science

1. Which statement best distinguishes a closed system from an open system in mass investigations?

   Closed: no matter enters or leaves; open: matter can enter or leave. Key difference is whether matter can cross system boundaries.

2. What should be included in the mass measurement when testing conservation in a sealed bag reaction?

   All contents plus the container (bag) each time. Container mass must be included for accurate total measurement.

3. Which type of system must be used to accurately show mass conservation when gas may form?

   A closed system (sealed container). Sealing prevents gas from escaping, ensuring accurate measurements.

4. Identify the best tool to measure mass before and after a change to test conservation of matter.

   A balance (such as a digital scale). Balances precisely measure mass in grams or kilograms.

5. Which unit is most appropriate for measuring the mass of a small object in a lab?

   Grams (g). Standard metric unit for small masses in science.

6. What is the expected mass change in a closed system after a change if matter is conserved?

   No change; initial mass equals final mass. Conservation means total mass remains constant.

7. What does it indicate if the mass decreases in an open system during a change that makes a gas?

   Matter likely escaped the system (gas left). Open systems allow gases to escape, reducing total mass.

8. What is the correct conclusion if measured mass decreases in an open system during a reaction?

   Matter likely escaped (often as a gas). Mass loss in open systems indicates matter left the system.

9. Find $m_{\text{after}}$ if $m_{\text{before}}=42\,g$ in a closed system and matter is conserved.

   $42\,g$. Conservation means mass remains unchanged.

10. Identify the best claim if bubbles form but the mass of a sealed flask stays the same.

    Gas formed but stayed inside; total matter was conserved. Sealed container trapped gas, conserving mass.

11. Which option is a chemical change: dissolving sugar or rusting iron?

    Rusting iron. Chemical changes create new substances with different properties.

12. Identify the best evidence that matter is conserved: same volume or same mass before and after?

    Same mass before and after. Mass measures matter quantity; volume can change without matter loss.

13. Identify the best evidence statement for conservation: "The mass was the same before and after in a sealed bag."

    Equal mass before and after in a closed system supports conservation of matter. This directly demonstrates the law of conservation of matter.

14. Which statement best describes what happens to mass during freezing in a closed container?

    Mass stays the same even though the liquid becomes a solid. Freezing changes state but conserves total mass.

15. Which option is a physical change: melting ice or burning paper?

    Melting ice. Physical changes alter form but not chemical composition.

16. Identify the best conclusion if a sealed bag has mass $25.0\,g$ before and $25.0\,g$ after a reaction.

    Matter was conserved in the closed system. Equal masses before and after prove conservation.

17. What does it mean to say matter is conserved during a physical or chemical change?

    Total mass stays the same; matter is not created or destroyed. Matter cannot be created or destroyed, only transformed.

18. What does it mean to say that matter is conserved during a change?

    Total mass stays the same; matter is not created or destroyed. Matter cannot be created or destroyed, only rearranged.

19. Which statement is correct: mass can change, or mass stays constant in a closed system?

    Mass stays constant in a closed system. Conservation law requires mass remains unchanged in closed systems.

20. What is the difference between an open system and a closed system in mass measurements?

    Open: matter can enter or leave; closed: matter cannot enter or leave. Closed systems prevent matter exchange with surroundings.

21. Which option is the best way to prevent loss of matter when heating causes evaporation?

    Use a covered or sealed container to keep vapor inside. Sealing prevents water vapor from escaping during heating.

22. Choose the correct comparison for conservation of matter: $m_\text{before}$ ___ $m_\text{after}$ in a closed system.

    $m_\text{before} = m_\text{after}$. Conservation requires mass equality before and after changes.

23. Identify the best statement about particles when mass is conserved during a change.

    Particles are rearranged or change state; the number of particles stays the same. Conservation means same number of particles exist.

24. What does it indicate if the mass increases in an open system during a change?

    Matter likely entered the system (for example, gas from air). Open systems allow matter exchange with surroundings.

25. What does it mean if the mass before and after a change is equal in a closed system?

    Matter was conserved during the change. Equal mass before and after proves no matter was lost or gained.

26. What measurement is most commonly used as evidence that matter is conserved?

    Mass (often measured in grams). Mass directly measures the amount of matter present.

27. Which statement best describes what happens to mass during condensation in a sealed container?

    Mass stays the same; gas becomes liquid but remains in the container. Phase change occurs but all matter stays contained.

28. Which tool is most appropriate to measure mass accurately in a conservation-of-matter lab?

    A balance or scale. These instruments precisely measure mass in grams.

29. Which option shows conservation of mass: A) $10\,g\to 8\,g$ B) $10\,g\to 10\,g$ C) $10\,g\to 12\,g$?

    B) $10\,g\to 10\,g$. Only equal masses demonstrate conservation.

30. Identify the best claim if mass changes from $80\text{ g}$ to $76\text{ g}$ in an open cup during bubbling.

    Matter escaped as gas; the system was open. Mass decrease indicates gas bubbles escaped the open container.

31. Calculate the final mass if $m_{before} = 125\text{ g}$ in a sealed container.

    $125\text{ g}$. In sealed containers, mass remains constant during changes.

32. What is the correct conclusion if measured mass increases in an open system during a reaction?

    Matter likely entered (often oxygen from air). Mass gain in open systems indicates matter entered from outside.

33. What is the law of conservation of matter during a physical or chemical change?

    Matter is not created or destroyed; total mass stays the same. This fundamental law applies to all physical and chemical changes.

34. Which system must be used to show conservation of matter when a gas might be produced?

    A closed system (sealed container). Prevents gas from escaping, ensuring all matter stays inside.

35. What total mass should be measured after combining $30\text{ g}$ and $45\text{ g}$ in a sealed container?

    $75\text{ g}$. Add masses: $30\text{ g} + 45\text{ g} = 75\text{ g}$ total.

36. Identify the correct claim: dissolving changes total mass, or it keeps total mass the same?

    It keeps total mass the same in a closed system. Dissolved substances still contribute to total mass.

37. Decide if matter was conserved: $m_{before}=80\text{ g}$ and $m_{after}=78\text{ g}$ in an open cup.

    Not shown; matter likely escaped to the air. The $2\text{ g}$ loss suggests gas escaped the open container.

38. Which instrument is typically used to measure mass in a classroom conservation experiment?

    A balance (such as a triple-beam or digital balance). Balances measure mass precisely for conservation experiments.

39. What is a common reason mass appears to decrease during evaporation in an open cup?

    Gas particles escape into the air, so matter leaves the system. Open systems allow matter to escape, reducing mass.

40. Choose the correct conclusion: In a sealed bottle, mass stays $35\text{ g}$ after bubbling starts. What does this show?

    Gas formed, but matter was conserved. Bubbles don't change total mass in sealed systems.

41. Which evidence best supports conservation of matter: temperature change or unchanged mass in a sealed system?

    Unchanged mass in a sealed system. Mass measurement directly proves conservation.

42. Decide if matter was conserved: $m_{before}=50\text{ g}$ and $m_{after}=50\text{ g}$ in a sealed bag.

    Yes, matter was conserved. Equal masses before and after confirm conservation.

43. Choose the correct conclusion: A sealed flask is $200\text{ g}$ before and $201\text{ g}$ after. What is most likely?

    Measurement error; mass should stay constant in a closed system. Small differences suggest scale precision limits, not actual change.

44. What measurement is most direct evidence that matter is conserved in a closed system?

    Mass measured before and after the change is the same. Conservation means initial and final masses are equal.

45. Which statement best describes what happens to mass during evaporation in a sealed container?

    Mass stays the same; liquid becomes gas but remains in the container. Sealed containers trap gas, preserving total mass.

46. Which statement best describes what happens to mass during melting in a closed container?

    Mass stays the same even though the state of matter changes. Phase changes don't affect total mass in closed systems.

47. A bag has $18\,g$ of reactants and stays sealed; the products measure $18\,g$. What does this show?

    Mass was conserved; matter was rearranged, not lost or gained. Equal masses prove conservation occurred.

48. Find the missing mass: $m_{before}=200\text{ g}$, one product is $120\text{ g}$ in a closed system. What is the other product mass?

    $80\text{ g}$. Conservation requires total products equal initial mass: $200-120=80$.

49. Identify the claim supported by data: sealed bag has $m_{before}=15.0\text{ g}$ and $m_{after}=15.0\text{ g}$ after mixing.

    The total mass stayed the same; matter was conserved. Equal masses demonstrate conservation of matter.

50. What conclusion is supported if a sealed bag has mass $50\text{ g}$ before and $50\text{ g}$ after mixing?

    Matter was conserved in the closed system. Equal masses before and after prove no matter was lost or gained.

51. What measurement is most often used as evidence that matter is conserved in an investigation?

    Mass (measured with a balance). Mass directly measures the amount of matter present.

52. What is the mass change if a closed container is $120\text{ g}$ before and $120\text{ g}$ after a reaction?

    $0\text{ g}$. Subtract: $120\text{ g} - 120\text{ g} = 0\text{ g}$ change.

53. Identify which setup best tests conservation of matter when heating water: open cup or sealed container?

    Sealed container. Sealing prevents water vapor from escaping during heating.

54. Identify the best conclusion if a sealed container changes from liquid to gas and mass stays constant.

    A state change does not change total mass in a closed system. Phase changes conserve mass when no matter escapes.

55. Find the final mass: In a closed system, initial mass is $150\text{ g}$. What is the final mass?

    $150\text{ g}$. Closed systems maintain constant mass throughout any change.

56. A reaction in an open cup goes from $30\,g$ to $28\,g$. What is the most likely explanation?

    Gas escaped; the system was open so matter left. Mass loss indicates matter escaped the system.

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