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?

    • 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
    • Copper has no bonds between its atoms, so its layers can flow like a liquid under a hammer

  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. Eggs slide off a PTFE-coated pan. What best explains it, Milo?

    • PTFE slowly melts a thin layer of its own oil, and the food slides on that oil layer
    • Fluorine atoms around the carbon chains attract other molecules weakly, so little sticks
    • PTFE atoms carry a strong charge that pushes food away from the pan's surface

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

    • The plastic repels electrons because it is charged negatively
    • The plastic is thick enough that electrons cannot squeeze through
    • 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
    • Natural rubber only, since it is the most flexible
    • PVC plastic and natural rubber, which both insulate well

  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 alone, since rubber's total of 12 cannot beat PVC's 13
    • PVC plastic and natural rubber, with totals of 13 and 12

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

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

    • 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
    • Copper has no bonds between its atoms, so its layers can flow like a liquid under a hammer

  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. Eggs slide off a PTFE-coated pan. What best explains it, Milo?

    • PTFE slowly melts a thin layer of its own oil, and the food slides on that oil layer
    • Fluorine atoms around the carbon chains attract other molecules weakly, so little sticks
    • PTFE atoms carry a strong charge that pushes food away from the pan's surface

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

    • The plastic repels electrons because it is charged negatively
    • The plastic is thick enough that electrons cannot squeeze through
    • 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
    • Natural rubber only, since it is the most flexible
    • PVC plastic and natural rubber, which both insulate well

  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 alone, since rubber's total of 12 cannot beat PVC's 13
    • PVC plastic and natural rubber, with totals of 13 and 12

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

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