Chemistry Using Earth's Resources March 2019 Flashcards
What are the Earth’s resources? What are they used for?
- Rocks in the ground = Make metals from ores and buildings for stone, sand and brick (clay).
- Fuels such as coal, natural gas and oil = Fuel for transport, electricity, heating, clothes, plastic and some medicines
- Plants and animals = Food, buildings and medicines.
- Fresh water and sea water = Drinking, agriculture and energy.
- Air = Respiration and combustion.
- Sunlight = Energy and agriculture.
- Wind = Energy.
What are finite and renewable resources?
Finite = A resource that cannot be replaced once it has been used.
Renewable = A resource that we can replace once it has been used.
What is sustainable development?
Using resources to meet the needs of people today without preventing people in the future from meeting theirs.
How can sustainable development be used for different resources?
Metals - Recycle materials instead of throwing them away and using more metal ores.
Fuels - Use bio-fuels (e.g. bio-diesel or ethanol) instead of fossil fuels.
Electricity - Use renewable energy sources instead of fossil fuels.
How are different materials recycled?
Metals - Separated, melted then reformed.
Glass - Separated into colours, melted then remoulded.
Plastics - Separated into types, melted then remoulded.
What is a life cycle assessment?
An examination if the impact of a product on the environment throughout it’s life.
What is potable water?
Water that is safe to drink.
What are the different types of water?
Pure water - Water that contains only water molecules and nothing else.
Potable water - Water that is safe to drink.
Fresh water - Water found in rivers, lakes, ice caps and glaciers.
Ground water - Fresh water in underground streams and in porous rocks.
Sea water - Water in the seas and oceans.
Waste water - Used water from homes, industry and agriculture.
What are the contents of the different types of water?
Pure - Nothing
Potable - Low-levels of dissolved substances.
Fresh - Low-levels of microbes and low-levels of dissolved substances.
Ground - Microbes and low-levels of dissolved substances.
Sea - Microbes and high-levels of dissolved substances.
Waste - Microbes and high-levels of dissolved substances.
What is desalination?
A process to remove dissolved substances from sea water.
How does distillation work?
Sea water is heated so that it boils. The water molecules are turned to steam leaving behind the dissolved substances. The water vapour is then cooled and condensed.
How does reverse osmosis work?
Sea water is passed through a semi-permeable membrane using pressure. The water molecules pass through the membrane but many of the dissolved substances cannot. This is the opposite of normal osmosis where the water would move in the opposite direction.
What is an ore?
A rock from which a metal can be extracted for profit.
What is an alloy?
A mixture of a metal with small amounts of other metals or carbon.
What are different alloys made of? What are their purposes?
Bronze - Copper and Tin, used to make decorative objects.
Brass - Copper and Zinc, Used to make door fittings, water taps and instruments (trumpet etc).
Gold alloys - Gold and Silver/Copper/Zinc, used to make jewellery.
Steels - Iron and usually Carbon. Used to make cars, building frameworks, cutlery and tools.
Aluminium-Magnesium alloys - Aluminium and Magnesium. Used to make aeroplanes.
What are corrosion and rusting?
Corrosion = The destruction of materials by chemical reactions with substances in the environment.
Rusting = The corrosion of iron or steel.
What is the chemical equation for rusting?
Iron + water + oxygen –> Rust
What two ways are used to stop the corrosion of materials?
Surface coating and sacrificial protection.
What is sacrificial protection? How does it work?
Sacrificial protection is preventing a metal from corrosion by attaching it to a more reactive metal that corrodes in it’s place. E.g. zinc or magnesium blocks being attached to the hull of ships to prevent the corroding of the steel.
What is surface coating? How does surface coating work?
Surface coating is when a substance is used to cover the material and act as a barrier. it prevents chemicals that cause corrosion from coming into contact with the material. E.g. Paint on a car or grease on a chain.
What are the processes of bioleaching and leaching?
Bioleaching - The use of bacteria to produce soluble metal compounds from insoluble metal compounds.
Leaching - The use of dilute acid to produce soluble metal compounds from insoluble metal compounds.
What is a leachate?
A solution produced by leaching or bioleaching.
What is phytomining?
The use of plants to absorb metal compounds from soil as part of metal extraction.
How is copper extracted?
Copper ores - low-grade copper ores are used as there a no longer high-grade ones. Bioleaching or leaching is then done to the ore to give a copper leachate. Electrolysis or a displacement reaction with scrap iron then takes place to give the copper metal.
Plants - Plants are grown in soil containing copper compounds. The plants are then burnt and bioleaching or leaching then takes place to give a copper leachate. Electrolysis or a displacement reaction with scrap iron then takes place to give the copper metal.
