IB myp 4-5 Chemistry – Practice Questions- All Topics
Topic :IUPAC-Structural Formulas
Topic :IUPAC- Weightage : 21 %
All Questions for Topic : Alkanes,Alkenes,Alcohols,Carboxylic Acid,Esters,Structural Formulas
Question (8 marks) – Evaluating Fabrics for Sportswear
Background:
The fashion industry uses various textiles with different properties. New synthetic materials raise sustainability considerations.
a. (1 mark) Polyester forms when an alcohol and carboxylic acid react to make an ester. Identify the alcohol in this reaction:
Select one option:
▶️ Answer & Explanation
Correct Answer: B (HO-)
Chemical Basis:
- Polyester formation requires a diol (alcohol with two -OH groups)
- General reaction: HO-R-OH + HOOC-R’-COOH → [-O-R-O-CO-R’-CO-]n + H2O
- Option B represents the alcohol component (HO-R-OH)
b. (7 marks) Evaluate fabric suitability for sportswear using this data:
| Property | Cotton | Silk | Satin (Silk+Polyester) |
Velvet (Silk+Rayon) |
Polyester | Nylon |
|---|---|---|---|---|---|---|
| Fiber Type | Natural | Natural | Mixed | Mixed | Synthetic | Synthetic |
| Breathability* | 60% | 20% | 60% | 20% | 20% | 0% |
| Wrinkle Resistance | No | Yes | Yes | Yes | Yes | Yes |
| Primary Function | Comfort | Warming | Formalwear | Luxury | Durability | Waterproofing |
| Machine Washable | Yes | No | Yes | No | Yes | Yes |
| Cost | Low | High | Medium | High | Low | Medium |
*Breathability: Ability to allow sweat evaporation
▶️ Answer & Explanation
Marking Guide (7 marks):
| Criteria | 1 mark | 2 marks | 3 marks |
|---|---|---|---|
| Properties | States one relevant property (e.g., breathability) | States two properties OR one with sportswear link | Two+ properties with sportswear links |
| Comparison | Compares 2 fabrics | Compares 3+ fabrics | – |
| Opinion | States a choice | Choice with justification | – |
Exemplar Response:
- Key Properties for Sportswear:
- High breathability (60% cotton/satin > 20% polyester)
- Wrinkle resistance (all except cotton)
- Machine washable (excludes silk/velvet)
- Comparison:
- Cotton: Breathable but wrinkles
- Polyester: Durable but less breathable
- Satin: Best balance (60% breathability + wrinkle resistance)
- Recommended Choice: Satin (mixed)
- Justification: Combines silk’s comfort with polyester’s durability
- Alternative: Cotton-polyester blend for cost efficiency