C14.1 - C14.6 - Using Earths Resources✔️ Flashcards
What are finite resoruces?
Resources that are being used up faster than they can be replaced - there is limited amount
What are renewables?
Resources that can be replaced a the same rate at which they are used up
Why are synthetic products produced?
Chemists provide new synthetic products which supplement or replace natural products - this helps reduce our reliance on natural products
Give three examples of renewable resources?
- wood
- leather
- cotton
What are synthetic products?
Products which supplement or replace natural products
Give each step for sewage treatment?
Water water flows from sewer to treatment plant where it is screened which removes grit and large objects - it then pases through a primary sedimentation tank then through an aeration tank before a final settling tank and into the enviorment
What does screening do to sewage?
Removes large solids and grit from the waste water by passing waste through a metal grid
What does primary sedimentation tanks do?
Organic waste sinks to the bottom as sludge - remianing water (effluent) taken from the top
What does the aeration tank do?
Good bacteria kill harmful bacteria in aeration tanks where is air is pumped through effluent which helps the good/uesefull bacteria as they are normally aerobic
What happens to the sludge from sewage?
Removed by the primary sedimentation tank and then digested anaerobicaly by bacteria which releases methane which is used to generate electricity - can also be dried and used as ferteliser on farmland to improve the soil
Give two ways copper metal can be obtained from copper ore?
- sulfuric acid is used to produce copper sulfate solution, before extracting the copper metal
-through smelting - copper ore is heated to a high temperature in a furnace with air, to produce impure copper
How can we obtain pure copper from impure copper produced through smelting copper ore?
Impure copper is used as the positive electrode in electrolysis cells to make pure copper
Issues with obtaining pure copper from smelting and electrolysis? Give 2 reasons?
Requires huge amounts of energy and electricity which is expensive and causes pollution of the enviorment
explain in depth how pure copper can be obtained through phytomining?
Plants absorb low-grade copper ions from the soil they are grown in - plants are then burned and the copper is extracted from copper compounds in the ash - the copper ions can be ‘leached’ producing a solution of copper sulfate - displacement by scrap ion and then electorlysis makes pure copper metal
Why is the the copper ions ‘leached’ from the ash during phtomining?
Copper ions can be ‘leached’ (dissolved) from the ash by adding sulfuric acid which makes a solution of copper sulfate
Explain the process of bioleaching, to produce pure copper?
Bacteria feed on low-grade metal ores by a combination of biological and chemical processes, a solution of copper ions (leachate) can be obtained from waste copper ore - scrap iron and electrolysis is used to extract the copper from the leachate
Explain why life cycle assesments are carried out (LCAs)?
Carried out to assess the enviormental impacts of products,processes or services
What are the four stages the impacts on the enviorment by products are assessed through LCAs?
• extracting and processing raw materials
• manufacturing and packaging
• use and operation during its lifetime
• disposal at the end of its useful life, including transport and distribution at each stage.
Give the order of the stages in an LCA?
Raw material extraction → manufacture → use/reuse/maintenance → recycle/waste management
What is an LCA? issues with them?
Provides an estimate of the total enviormental impacts resulting from all stages in the products life cycle - assigning numerical values to the relative effects of pollutants involves subjective judgement aswell as this they do not take into account differences in the cost or performance
What is portable water?
Water that is safe to drink - should have sufficiently low levels of dissolved salts and microbes
Example of some of the sterilising agents used for portable water?
- chlorine
- ozone
- ultraviolet light
How can fresh water be treated to make is safe to drink?
passing untreated water through filter beds made of sand and gravel to remove solid particles and adding chlorine or ozone to sterelise the water by killing microrganisms or by using ultraviolet light
How can countries that do not have access to large volumes of fresh water obtain the needed water?
Through desalination of salty water or sea water which is done by distilation or by processes that use membranes such as reverse osmosis - these process require large amounts of energy
Explain how glass bottles for example can be reused?
Glass bottles can be crushed and melted to make different glass products
How can meltals be recycled?
By melting them and recasting or reforming into different products
Name two products which could be reused?
- glass bottles
- plastic carrier bags
