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Grade 8 Science — The particulate nature of matter

Explain the three states of matter by how tightly their particles are held and how much space sits between them.

Name: ________________________

  1. 1.Grinding a stick of chalk into fine powder is which kind of change, and why?

    • a) A physical change, because heat was needed to do it
    • b) A chemical change, because the chalk cannot be put back together
    • c) A physical change, because the chalk is still chalk and just the size of each speck has altered
    • d) A chemical change, because the powder is a new substance

  2. 2.In the chapter's table, ice melts at 0 °C and urea at 133 °C. The third solid listed melts at 1538 °C. Which solid is that? Give the one word.

  3. 3.Now sort the same three by how much room sits between their particles.

    Groups: Least space between particles · A little more space than in a solid · Most space between particles

    • Gas
    • Liquid
    • Solid

  4. 4.Match each solid from the chapter's table to its melting point, in degrees Celsius.

    • Ice
    • Urea
    • Iron
    • 133
    • 1538
    • 0

  5. 5.Liquids and gases share two properties that solids do not: they flow, and they do not hold a fixed shape. What are the two of them called together?

    • a) Mixtures
    • b) Fluids
    • c) Vapors
    • d) Solutions

  6. 6.A solid is heated until it melts. Put the four stages back into order.

    • The solid turns into a liquid
    • The particles vibrate more vigorously
    • The vibrations grow strong enough that particles leave their positions
    • The interparticle forces of attraction weaken

  7. 7.An incense stick is lit in one corner of a room and the fragrance is soon noticed across it. What does that show?

    • a) Smoke is heavier than air and rolls along the floor
    • b) Air particles stand still while the fragrance particles push past them
    • c) The fragrance particles are pulled towards people
    • d) The particles of air are moving constantly and carry the fragrance particles with them

  8. 8.Match each state of matter to what it does about shape and volume.

    • A solid
    • A liquid
    • A gas
    • keeps neither shape nor volume, and spreads through the space available
    • keeps a definite shape and a definite volume
    • keeps a definite volume but takes the shape of its container

Answer key — Grade 8 Science — The particulate nature of matter

  1. 1. c) A physical change, because the chalk is still chalk and just the size of each speck has altered
  2. 2. iron
  3. 3. Solid → Least space between particles; Liquid → A little more space than in a solid; Gas → Most space between particles
  4. 4. Ice → 0; Urea → 133; Iron → 1538
  5. 5. b) Fluids
  6. 6. 1. The particles vibrate more vigorously 2. The vibrations grow strong enough that particles leave their positions 3. The interparticle forces of attraction weaken 4. The solid turns into a liquid
  7. 7. d) The particles of air are moving constantly and carry the fragrance particles with them
  8. 8. A solid → keeps a definite shape and a definite volume; A liquid → keeps a definite volume but takes the shape of its container; A gas → keeps neither shape nor volume, and spreads through the space available