Using resources

• What do humans rely on Earth's resources for? [4] - Warmth - Shelter - Food - Transport
• What do all our resources come from? Earth's crust, oceans and atmosphere
• What is a finite resource? Non-renewable
• What is an example of a finite resource? Metal ores
• What are renewable resources? Resources that can be replenished
• What is an example of renewable resources? Timber
• Why should care be taken with non-renewable resources? To ensure they do not pollut the planet.
• What was the abundancy of natural resources like in the past? Natural resources were sufficient to provide the human population with food, timber, clothing and fuels
• What has happened as the population of humans have increased? Humans have come to rely more on agriculture to supplement or even replace resources
• How does Chemistry play an important role in improving agricultural and industrial processes? [2] - Allows new products to be developed - Contributes to sustainable development
• What is sustainable development? Development that meets the needs of the current generation without comprimising the ability of future generations to meet their own needs
• Is water of the correct quality essential for life? Yes
• What does water naturally contain? Microorganisms and dissolved salts
• Why does there need to be low levels of microorganisms and dissolved salts in water? So its safe for humans to drink
• What does fresh water contain? Low levels of dissolved salts
• What does the term potable mean? Water that is good quality and safe to drink
• In the UK, how is potable water produced? [4] - Fresh water from a suitable source (lake or river) is collected - Passed through a filter bed to remove solid particles - Chlorine gas is added to kill any harmful microorganisms - Fluoride is added to drinking water to reduce tooth decay
• Why is too much fluoride bad? Can cause discolouration of teeth
• What does ozone and ultraviolet do to water? Sterlises water
• How do you improve the taste and quality of tap water? By removing more dissolved substances by passing the water through a filter containing carbon, silver and iron exchange resins
• What would happen if fresh water supplies are limited? [2] - Seawater can be desalinated to produce pure water. - This can be done by distillation or reverse osmosis
• What is the con of reverse osmosis and desalination when attempting to produce pure water? Both of these processes require lots of energy, thus making them very expensive
• What happens during distillation? [2] - Water is boiled to produce steam - Steam is condensed to produce pure liquid water
• What does pure water contain? No dissolved substances
• What are large amounts of waste water produced by? [3] - Homes - Agricultural processes - Industrial processes
• What must happen to waste water before it can be released back into the enviroment? Must be treated
• What does sewage treatment include? [4] - Screening and grit removal - Sedimentation to produce sewage sludge and effluent - Anaerobic digestion of sewage sludge - Aerobic biological treatment of effluent
• Why is copper a useful metal? [3] - Good conductor of heat & electricity - Easily bent, yet hard enough to make water pipes and tanks - Does not react with water
• Where is copper extracted from? Copper-rich ores
• How is copper extracted from copper-rich ores? By heating the ores with carbon in a furnance. This is known as smelting
• What happens when the copper is smelted? It is purified by electrolysis
• How else can copper also be obtained? [2] - From solutions of copper salts by electrolysis - By displacement using a scalp iron
• What happens during electrolysis of copper? Positive copper ions move towards the negatve electrode and form pure copper
• The extensive mining of copper in the past, has meant that? We're running out of copper-rich ores
• What has occured to combat the decrease in copper-rich ores? New methods have been developed to extract it from ores that contain less copper
• What can copper be extracted from to combat the decrease of copper-rich ores? [2] - Low grade ores - Contaminated land by biological methods
• What is Phytomining? A method that uses plants to absorb copper
• What happens during Phytomining? [2] - As plants grow, they absorb (and store) copper - The plants are then burned and the ash produced contains copper in a relatively high quantities
• What is bioleaching? Uses bacteria to extract metals from low-grade ores
• What happens during bioleaching? [2] - Solution containg bacteria is mixed with a low-grade ore - The bacteria converts the copper into a solution (leachate solution), from which the copper can easily be extracted