| Lesson Plan |
| Grade: |
Date: 25/02/2026 |
| Subject: Chemistry |
| Lesson Topic: Describe how the properties of fractions obtained from petroleum change from the bottom to the top of the fractionating column, limited to: (a) decreasing chain length (b) higher volatility (c) lower boiling points (d) lower viscosity |
Learning Objective/s:
- Describe how chain length, volatility, boiling point, and viscosity change from the bottom to the top of a fractionating column.
- Explain the molecular reasons for these trends, focusing on intermolecular forces and energy requirements.
- Interpret a schematic of a fractionating column to identify typical petroleum fractions and their associated properties.
- Apply knowledge of fraction properties to suggest appropriate industrial uses for each fraction.
|
Materials Needed:
- Projector or interactive whiteboard
- Slide deck with a fractionating‑column diagram
- Handout summarising typical fractions and their properties
- Whiteboard and markers
- Sample images of petroleum products (optional)
- Exit‑ticket cards for the conclusion activity
|
Introduction:
Begin with a short video of a refinery’s fractionating column to capture interest. Ask students to share everyday petroleum products they use and discuss prior knowledge of oil separation. Explain that by the end of the lesson they will be able to describe the systematic changes in chain length, volatility, boiling point and viscosity from the bottom to the top of the column.
|
Lesson Structure:
- Do‑now (5') – Students list daily petroleum products and discuss in pairs; teacher records examples on the board.
- Mini‑lecture (10') – Explain how a fractionating column works, the temperature gradient, and introduce the four property trends.
- Guided analysis (12') – In groups, students use the provided table to match each fraction with its chain length, boiling point, volatility and viscosity, completing a worksheet.
- Concept check (8') – Whole‑class quiz (clickers or show of hands) to confirm understanding of why properties change (intermolecular forces).
- Application activity (10') – Groups choose a fraction, propose a practical use, and justify it using the fraction’s physical properties; share findings.
- Summary & exit ticket (5') – Students write one sentence summarising the overall trend and answer a quick exit question on a card.
|
Conclusion:
Recap the key trend: moving up the column shortens carbon chains, lowers boiling points and viscosity, and increases volatility.
Collect exit tickets to gauge immediate understanding and address any remaining misconceptions.
Homework: complete a worksheet that requires labeling a blank fractionating‑column diagram and explaining why each fraction is suited to a specific application.
|