Polymers, Materials & Chemical Design — Practice · Grade 11 Science

Chapter: Organic Chemistry & Material Design

What this practice covers

By the end of Polymers, Materials & Chemical Design you should be able to:

8 questions, numeric and written answer, each with a worked explanation.

Vocabulary used: monomer, cross-link, thermoplastic.

Problem 1

Repeat-unit mass 44 g/mol and 200 units: estimated chain mass?
Hints

Write the relationship first; substitute with consistent units.

Answer and explanation

8800 g/mol

44×200=8800.

Problem 2

Does fragmenting into microplastic establish biodegradation?
Answer and explanation

No. The polymer can remain chemically present in smaller particles.

Response criteria

  • State a scientifically accurate conclusion.
  • Show the calculation or mechanism that supports it.
  • Include units, conditions, or limits where relevant.

Problem 3

Repeat-unit mass is 50 g/mol and an ideal chain has 300 units. Estimate chain molar mass ignoring ends.
Hints

List the given quantities, select a relationship, and check units before substituting.

Answer and explanation

15000 g/mol

50×300=15000.

Problem 4

What should a compostability comparison specify?
Answer and explanation

Temperature, moisture, biological conditions, timescale, test criteria, and access to appropriate processing.

Response criteria

  • State a scientifically accurate conclusion.
  • Show the calculation or mechanism that supports it.
  • Include units, conditions, or limits where relevant.

Problem 5

How can cross-linking change a polymer's behavior? Show the reasoning, not just the conclusion.
Hints

Polymer properties depend on chain structure, additives and processing.

Answer and explanation

Links between chains can restrict movement, often increasing rigidity or elastic network behavior depending on structure.

Problem 6

Why should a biodegradable label be checked against actual disposal conditions?
Hints

State what the supplied observations or conditions establish, and separate that from any assumption.

Answer and explanation

Degradation depends on temperature, moisture, organisms and timescale; a label does not guarantee rapid breakdown in every environment.

Problem 7

A material’s life-cycle claim needs a defined service and system boundaryA material’s life-cycle claim needs a defined service and system boundaryEvidence boundaryQuestion before comparing materialsServiceWhat function, durability and failure conditions?ProductionWhich energy/material inputs are included?End of lifeIs collection and the actual processing routeavailable?Environmental outcomeWhat emissions, leakage and breakdown conditions?A label such as bio-based does not settle the full impact account.
Original comparison-boundary organizer, not a ranking of current commercial products or a claim about a specific recycling system.
Interpret the supplied visual. Why does biodegradable not prove that an item will break down rapidly in every ocean, landfill or backyard condition?
Answer and explanation

Breakdown depends on material, organisms, temperature, moisture and time; the label requires specified test conditions and does not establish every disposal outcome.

A life-cycle comparison evaluates a defined service across selected production, use and end-of-life stages. Bio-based, biodegradable and recyclable describe different claims: feedstock origin, breakdown under specified conditions, and recovery/process feasibility. None automatically establishes the others or the lowest total impact. Mass alone can be a misleading comparison if products have different lifetimes or functions. Identify local collection, contamination, energy and leakage evidence before turning a material label into an environmental conclusion.

Breakdown depends on material, organisms, temperature, moisture and time; the label requires specified test conditions and does not establish every disposal outcome.

Response criteria

  • Interpret labels, structures, axes, units and directions correctly.
  • Explain the chemistry relationship or mechanism.
  • Respect stated assumptions and distinguish observation from inference.

Problem 8

A part needs load index ≥70. P scores load 80, input 40 and 20 cycles; Q scores load 65, input 24 and 30 cycles; R scores load 90, input 30 and 10 cycles. Select a feasible option by input per cycle and name a missing criterion.
Answer and explanation

Q fails the load constraint. Among feasible P and R, P uses 40/20=2 input units/cycle versus R’s 30/10=3, so P is preferred under this indicator. Cost, failure variability, repair, emissions or end-of-life evidence could change the broader decision.

Q fails the load constraint. Among feasible P and R, P uses 40/20=2 input units/cycle versus R’s 30/10=3, so P is preferred under this indicator. Cost, failure variability, repair, emissions or end-of-life evidence could change the broader decision.

Response criteria

  • Use the stated measurements or conditions, with correct units.
  • Connect the result to the chemical mechanism or evidence relationship.
  • Identify the assumption, model limit or further evidence requested.

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