Atmosphere & resources flashcards

Key points

• Volcanoes released the early atmosphere: mainly carbon dioxide, with little or no oxygen, plus water vapour and some nitrogen.
• The water vapour condensed to form the oceans.
• Carbon dioxide fell as it dissolved in the oceans and formed carbonate rocks, and as algae and plants took it in.
• Algae and plants photosynthesised, which is where the oxygen came from. It built up over about a billion years.

Formula

Key points

• About 78% nitrogen: roughly four-fifths.
• About 21% oxygen: roughly one-fifth.
• Small amounts of argon and the other noble gases, water vapour and carbon dioxide.
• Carbon dioxide is only about 0.04%, yet it matters a lot as a greenhouse gas.

0.04% carbon dioxide in a million

Key points

• Short wavelength radiation from the Sun passes through the atmosphere and warms the Earth's surface.
• The warm Earth gives off longer wavelength infrared radiation.
• Greenhouse gases absorb that infrared, so heat stays in the atmosphere.
• The main ones: carbon dioxide, methane and water vapour. Nitrogen and oxygen are not greenhouse gases.

Key points

• Carbon dioxide: burning fossil fuels, and deforestation, which also removes trees that take carbon dioxide in.
• Methane: cattle and other livestock, rice fields and rotting waste in landfill.
• More greenhouse gases trap more heat, so the Earth's average temperature rises.
• Likely effects: rising sea levels, more extreme weather, changes to rainfall, wildlife ranges and how much food can be grown.

Key points

• The total carbon dioxide and other greenhouse gases given off over the full life cycle of a product, service or event.
• It counts every stage: raw materials, making, transport, use and disposal.
• Reduce it with renewable energy, using energy efficiently (such as insulating homes) and cutting waste.
• Capturing carbon dioxide from power stations, and public transport, help too.

Key points

• Changes can be expensive, or less convenient, so people and businesses are slow to make them.
• People may not understand the problem or the science, so there is little pressure to act.
• Governments may not act without public support.
• Countries do not always agree to act together, and one country cutting alone changes little.

Key points

• Incomplete combustion happens when a fuel burns in too little oxygen.
• Carbon monoxide is toxic, with no colour or smell, so you cannot tell it is there.
• It joins onto the haemoglobin in red blood cells, so the blood carries less oxygen.
• Soot (carbon particulates) damages the lungs and causes global dimming by blocking sunlight.

Methane burning

Key points

• Sulfur dioxide forms when sulfur impurities in a fuel burn.
• Nitrogen oxides form in hot engines, where nitrogen and oxygen from the air react together.
• Both dissolve in rainwater to make acid rain, which damages buildings, statues, lakes and forests.
• Both cause breathing problems.
• Cut them by removing sulfur from fuels and fitting catalytic converters to cars.

Key points

• Potable water is safe to drink: low in dissolved salts and microbes. It is not pure in the chemical sense.
• Choose a source of fresh water, such as a reservoir, river or groundwater.
• Pass it through filter beds to remove solid particles.
• Sterilise it with chlorine, ozone or ultraviolet light to kill microbes.

Key points

• Desalination removes the salt from seawater.
• Distillation: boil the water, then cool and condense the steam, leaving the salt behind.
• Reverse osmosis: push the seawater through a membrane at high pressure, which holds the salt back.
• Both need a lot of energy, so they are costly and used where fresh water is scarce.

Key points

• pH: test with universal indicator paper or a pH probe. Pure water is pH 7.
• Dissolved solids: weigh an evaporating basin, evaporate a measured volume of the sample to dryness, then weigh again.
• Distillation: boil the sample, condense the steam in a condenser and collect the water.
• Pure water boils at 100 °C, so check the thermometer reading as it distils.

Solids left from 50 cm³ of sample

Key points

• A finite resource is used faster than it forms, such as crude oil and metal ores.
• A renewable resource is replaced as fast as it is used, such as timber from managed forests.
• Reduce, reuse and recycle make finite resources last longer and cut waste.
• Recycling aluminium takes a small fraction of the energy of extracting it by electrolysis, saves the ore and cuts mining waste.

Key points

• Its environmental impact at every stage, from cradle to grave.
• The stages: getting the raw materials, making it, using it and disposing of it, with transport in between.
• At each stage it adds up the energy, water and materials used, and the waste and pollution made.
• Some impacts, such as how harmful a pollutant is, are judgements, so an LCA is not fully objective.

Paper bag or plastic bag