Worksheet

Why a material's molecules decide what it can do

Grade 10 Science Worksheet - Building Confidence

NameDate

Circle the best answer, or write your answer on the line.

  1. A polyethylene chain has 1000 repeat units, each C₂H₄ with a mass of 28 g/mol. What is the chain's molar mass, Ari?

  2. A PTFE chain has 500 repeat units, each C₂F₄ with a mass of 100 g/mol. What is the chain's molar mass, Bo?

  3. A PVC chain has 600 repeat units, each C₂H₃Cl with a mass of 62.5 g/mol. What is the chain's molar mass, Esme?

  4. Hammered copper flattens, but a hammered salt crystal shatters. Which structural idea explains the difference, Jun?

    • Copper has no bonds between its atoms, so its layers can flow like a liquid under a hammer
    • Salt particles are lighter than copper atoms, so a hammer breaks them apart more easily
    • Metal layers slide while shared electrons hold them; sliding salt ions meet like charges

  5. Brass is harder to bend than pure copper. What best explains it, Kira?

    • Zinc atoms are lighter than copper atoms, so the metal packs more tightly together
    • Zinc atoms are a different size, so the layers of atoms cannot slide as easily
    • Brass has more free electrons than copper, so its bonds are stronger

  6. Graphite and diamond are both pure carbon, but only graphite conducts. Why, Luz?

    • Graphite has layers with free electrons; diamond's electrons are locked in bonds
    • Graphite has a little metal mixed in, while diamond has no metal inside it
    • Diamond atoms have no electrons of their own, so no electrons are available to carry current

  7. A copper wire is coated with plastic. Why does the plastic stop the current, Pia?

    • The plastic is thick enough that electrons cannot squeeze through
    • The plastic repels electrons because it is charged negatively
    • Its electrons stay in bonds, so none are free to carry current

  8. Read this first

    Wire coating scores (example scores, 1 to 5)

    materialflexibilityinsulationlow cost
    PVC plastic454
    natural rubber552
    copper313

  9. A coating needs an insulation score of at least 4 and a low-cost score of at least 3. Which material passes, Ren?

    • PVC plastic only, since rubber's cost score is 2
    • PVC plastic and natural rubber, which both insulate well
    • Natural rubber only, since it is the most flexible

  10. A coating needs an insulation score of at least 4 and a total of at least 12. Which materials pass, Tala?

    • Neither material, since a total of 12 is not above the limit of 12
    • PVC plastic and natural rubber, with totals of 13 and 12
    • PVC plastic alone, since rubber's total of 12 cannot beat PVC's 13

  11. Flexibility now counts triple, and the other two criteria count once. Which material has the highest total, Zee?

    • PVC plastic, the winner with 13 against 12 before weighting
    • Natural rubber, with 22 against PVC's 21
    • Copper, since its flexibility counts triple
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Why a material's molecules decide what it can do

Answer Key - Grade 10 Science Worksheet - Building Confidence

Circle the best answer, or write your answer on the line.

  1. A polyethylene chain has 1000 repeat units, each C₂H₄ with a mass of 28 g/mol. What is the chain's molar mass, Ari?

    28,000 g/mol

  2. A PTFE chain has 500 repeat units, each C₂F₄ with a mass of 100 g/mol. What is the chain's molar mass, Bo?

    50,000 g/mol

  3. A PVC chain has 600 repeat units, each C₂H₃Cl with a mass of 62.5 g/mol. What is the chain's molar mass, Esme?

    37,500 g/mol

  4. Hammered copper flattens, but a hammered salt crystal shatters. Which structural idea explains the difference, Jun?

    • Copper has no bonds between its atoms, so its layers can flow like a liquid under a hammer
    • Salt particles are lighter than copper atoms, so a hammer breaks them apart more easily
    • Metal layers slide while shared electrons hold them; sliding salt ions meet like charges

  5. Brass is harder to bend than pure copper. What best explains it, Kira?

    • Zinc atoms are lighter than copper atoms, so the metal packs more tightly together
    • Zinc atoms are a different size, so the layers of atoms cannot slide as easily
    • Brass has more free electrons than copper, so its bonds are stronger

  6. Graphite and diamond are both pure carbon, but only graphite conducts. Why, Luz?

    • Graphite has layers with free electrons; diamond's electrons are locked in bonds
    • Graphite has a little metal mixed in, while diamond has no metal inside it
    • Diamond atoms have no electrons of their own, so no electrons are available to carry current

  7. A copper wire is coated with plastic. Why does the plastic stop the current, Pia?

    • The plastic is thick enough that electrons cannot squeeze through
    • The plastic repels electrons because it is charged negatively
    • Its electrons stay in bonds, so none are free to carry current

  8. Read this first

    Wire coating scores (example scores, 1 to 5)

    materialflexibilityinsulationlow cost
    PVC plastic454
    natural rubber552
    copper313

  9. A coating needs an insulation score of at least 4 and a low-cost score of at least 3. Which material passes, Ren?

    • PVC plastic only, since rubber's cost score is 2
    • PVC plastic and natural rubber, which both insulate well
    • Natural rubber only, since it is the most flexible

  10. A coating needs an insulation score of at least 4 and a total of at least 12. Which materials pass, Tala?

    • Neither material, since a total of 12 is not above the limit of 12
    • PVC plastic and natural rubber, with totals of 13 and 12
    • PVC plastic alone, since rubber's total of 12 cannot beat PVC's 13

  11. Flexibility now counts triple, and the other two criteria count once. Which material has the highest total, Zee?

    • PVC plastic, the winner with 13 against 12 before weighting
    • Natural rubber, with 22 against PVC's 21
    • Copper, since its flexibility counts triple