ChemistryChapter 13: Environmental Chemistry-Air
Ozone Layer (stratosphere) — Ozone Cycle
UV splits O2, O joins O2 to O3, O3 later splits.
Learning objectives
- Define ozone cycle using accurate chemistry terms.
- Explain why ozone cycle matters within ozone layer (stratosphere).
- Apply the learning unit to an FBISE-style example, comparison, diagram, or calculation.
Definition
UV splits O2, O joins O2 to O3, O3 later splits. A steady shield. These notes do not teach how to thin it. Montreal Protocol phased CFCs — named success in policy questions. This page separates the idea from the wider topic “OZONE LAYER (STRATOSPHERE)” so it can be revised and assessed on its own.
Important terms
- OZONE CYCLE
- UV splits O2, O joins O2 to O3, O3 later splits.
- OZONE LAYER (STRATOSPHERE)
- O3 in the stratosphere absorbs UV.
Overview
Study this learning unit in three steps:
Key Idea
UV splits O2, O joins O2 to O3, O3 later splits. A steady shield. These notes do not teach how to thin it. Montreal Protocol phased CFCs — named success in policy questions.
Examples O2 / O / O3 · UV-B slogan · Not ground smog
Exam Application
Exam ozone contrast: stratosphere: O3 protects from UV troposphere: O3 in smog harms lungs CFCs named as old ozone-depleters, not a recipe
Examples O2 / O / O3 · UV-B slogan · Not ground smog
WHAT — OZONE LAYER (STRATOSPHERE) — OZONE CYCLE
UV splits O2, O joins O2 to O3, O3 later splits. A steady shield. These notes do not teach how to thin it. Montreal Protocol phased CFCs — named success in policy questions. This page separates the idea from the wider topic “OZONE LAYER (STRATOSPHERE)” so it can be revised and assessed on its own.
WHY — Why this topic matters
OZONE LAYER (STRATOSPHERE) — OZONE CYCLE is an independent FBISE learning unit because students must use its definitions, conditions, equations, or trends separately in explanations and calculations.
HOW — How it works
UV splits O2, O joins O2 to O3, O3 later splits. A steady shield. These notes do not teach how to thin it. Montreal Protocol phased CFCs — named success in policy questions. Examples: O2O / O3; UV-B slogan; Not ground smog. Exam use: Exam ozone contrast: stratosphere: O3 protects from UV troposphere: O3 in smog harms lungs CFCs named as old ozone-depleters, not a recipe
Explanation
UV splits O2, O joins O2 to O3, O3 later splits. A steady shield. These notes do not teach how to thin it. Montreal Protocol phased CFCs — named success in policy questions. Examples: O2O / O3; UV-B slogan; Not ground smog. Exam use: Exam ozone contrast: stratosphere: O3 protects from UV troposphere: O3 in smog harms lungs CFCs named as old ozone-depleters, not a recipe
In simple words
Federal Board Class 11 Chemistry learning unit. Easy wording; no provincial-board material added.
Key points
- absorb UV
- two ozones
Exam preparation
Exam Focus
Quick revision
Revision Zone
Review the key facts, formulas and checks before you move on.Ozone Layer (stratosphere) — Ozone Cycle
Sticky Notes · Quick Revision
Core idea
- UV splits O2, O joins O2 to O3, O3 later splits. A steady shield. These notes do not teach how to thin it. Montreal Protocol phased CFCs — named success in policy questions. This page separates the idea from the wider topic “OZONE LAYER (STRATOSPHERE)” so it can be revised and assessed on its own.
WHAT
- UV splits O2, O joins O2 to O3, O3 later splits.
WHY
- OZONE LAYER (STRATOSPHERE) — OZONE CYCLE is an independent FBISE learning unit because students must use its definitions, conditions, equations, or trends separately in explanations and calculations.
HOW
- UV splits O2, O joins O2 to O3, O3 later splits. A steady shield. These notes do not teach how to thin it. Montreal Protocol phased CFCs — named success in policy questions. Examples: O2O / O3; UV-B slogan; Not ground smog. Exam use: Exam ozone contrast: stratosphere: O3 protects from UV troposphere: O3 in smog harms lungs CFCs named as old ozone-depleters, not a recipe
Common misconception
- Do not treat ozone cycle as the same as every other part of ozone layer (stratosphere); define this unit and use its own evidence, steps, or conditions.
FBISE exam check
- Define ozone layer (stratosphere) — ozone cycle, explain how it works, and support the answer with one relevant example.
60-second revision
- UV splits O2, O joins O2 to O3, O3 later splits.
- O2O / O3
- Exam link: absorb UV.
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