GCSE Chemistry: Atmosphere & Using Resources — Revision Workbook

Inside GCSE Chemistry: Atmosphere & Using Resources — Revision Workbook

trace how the early atmosphere changed as oxygen increased and carbon dioxide fell, give the percentages of the main gases in air today, explain the greenhouse effect and how to cut a carbon footprint, identify the pollutants from burning fuels (carbon monoxide, soot, sulfur dioxide and nitrogen oxides), and tell finite from renewable resources while explaining potable water, life-cycle assessment, recycling, phytomining and bioleaching. About 30 minutes.

Learning objectives

• the evolution of the atmosphere — a volcanic, carbon-dioxide-rich early atmosphere, oceans dissolving carbon dioxide, and photosynthesis by algae and plants adding oxygen;
• the composition of air today — about 78% nitrogen, 21% oxygen and 0.04% carbon dioxide, with small amounts of noble gases and water vapour;
• greenhouse gases and climate change — carbon dioxide, methane and water vapour, the greenhouse effect, global warming and reducing a carbon footprint;
• atmospheric pollutants from burning fuels — carbon monoxide, soot/particulates (global dimming), and sulfur dioxide and nitrogen oxides (acid rain and respiratory problems);
• using resources — finite versus renewable resources and sustainable development, potable water and desalination, life-cycle assessment, reduce/reuse/recycle, and phytomining and bioleaching.

Activities in this book

1. Task 1 — Earth's Atmosphere Then & Now

   the early atmosphere came mainly from intense volcanic activity and was largely carbon dioxide, with little or no oxygen. As oceans formed, carbon dioxide dissolved; then algae and plants photosynthesised, adding oxygen and removing carbon dioxide. Today the air is roughly 78% nitrogen, 21% oxygen and about 0.04% carbon dioxide.

2. Task 2 — Greenhouse Gases & Climate Change

   greenhouse gases — carbon dioxide, methane and water vapour — absorb infrared radiation re-emitted by the Earth and keep the planet warm (the greenhouse effect). Human activities that release more of these gases are linked to global warming and climate change. The total greenhouse gases released over the life of something is its carbon footprint, which we can reduce.

3. Task 3 — Pollutants from Burning Fuels

   burning fuels releases pollutants. Incomplete combustion makes carbon monoxide (a toxic, colourless, odourless gas) and soot/particulates (which cause global dimming and breathing problems). Sulfur impurities burn to sulfur dioxide, and high engine temperatures make nitrogen oxides — both cause acid rain and respiratory problems.

4. Task 4 — Using Resources: Water & Recycling

   finite resources will run out; renewable ones are replaced. Potable water is safe to drink — fresh water is filtered and sterilised, and sea water can be desalinated. A life-cycle assessment weighs a product's whole-life impact. We reduce, reuse and recycle materials, and can extract metals from low-grade ores by phytomining (growing plants) and bioleaching (using bacteria).

5. Task 5 — Six-Mark Exam Task

   this is an extended six-mark question like the ones in the real exam. Plan a few points, use key words, and link cause to effect. Marks come from clear, well-organised science — not just a list.

Suggestions for teaching

• Tell the atmosphere's story in order. Volcanoes → carbon-dioxide-rich early air → oceans dissolve carbon dioxide → photosynthesis raises oxygen → today's stable mix.
• Fix the three percentages. Drill 78% nitrogen, 21% oxygen and 0.04% carbon dioxide until they are automatic, and link nitrogen to “about four-fifths”.
• Separate the two atmosphere problems. Keep greenhouse gases and warming clearly apart from pollutants such as carbon monoxide, particulates, sulfur dioxide and nitrogen oxides.
• Make resources concrete. Use real examples for potable water, recycling and phytomining/bioleaching, and model a short life-cycle assessment of an everyday object.