Flashcards in Environmental Problems Deck (32):
Burning fossil fuels release [ ] and particles
Which 2 things burn huge amounts of fossil fuels
Power stations and cars
Pure [ ] can also be used as a fuel. It only produces [ ] when burnt
Most fuels, such as crude oil and coal, contain [ ] and hydrogen. What happens during combustion?
carbon and hydrogen
The carbon and hydrogen are oxidised so that CO2 and water vapour are released into the atmosphere. Energy (heat) is also produced
hydrocarbon + oxygen ->
carbon dioxide + water vapour
If a fuel contains sulfur impurities, what is released when it burns?
What will form if a fuel is burnt at a high temperature?
Oxides of nitrogen
What is complete combustion?
When there's plenty of oxygen and all the fuel burns
What is partial combustion? What is the problem with this?
If there's not enough oxygen, some of the fuel doesn't burn.
Under these conditions, solid particles (particulates) of soot (carbon) and unburnt fuel are released. Carbon monoxide (a poisonous gas) is also produced
What gas causes acid rain?
Sulfur dioxide and oxides of nitrogen
How is acid rain 'made'?
When sulfur dioxide mixes with clouds it forms dilute sufuric acid then it falls as acid rain.
In the same way, oxides of nitrogen cause acid rain by forming dilute nitric acid in clouds
What does acid rain do to the environment?
Causes lakes to become acidic and many plants and animals die as a result.
Kills trees and damages limestone buildings and ruins stone statues.
Links between acid rain and human health problems have been suggested.
If acid rain is so bad for the environment, why do we still burn fuels that cause it? Is anything being doing to prevent acid rain?
The benefits of electricity and travel have to be balanced against the environmental impacts. International agreements have been put in place to reduce emissions of air pollutants such as sulfur dioxide.
Describe why we can / can't remove sulfur from fuels
Most of the sulfur can be removed from fuels before they're burnt but it costs more
Removing sulfur = more energy = comes from burning more fuel which releases more of greenhouse gas carbon dioxide
Petrol and diesel are starting to be replaced by low-sulfur versions
How do you reduce acid rain?
Power stations now have Acid Gas Scrubbers to take harmful gases out before they release the fume into the atmosphere.
Or. Reduce our usage of fossil fuels
Increasing carbon dioxide causes [ ]
The level of carbon dioxide in the atmosphere is [ ] - because of the large amount of [ ] that we burn
The extra carbon dioxide has caused the average [ ] of the Earth to increase - [ ]
Global warming is a type of [ ]
What can global warming cause?
Other types of climate change (changing rainfall patterns)
Severe flooding due to the polar ice caps melting
What is global dimming.
Where less sunlight is reaching earth due to particles of soot and ash in the air.
What causes global dimming?
Particles of soot and ash that are produced when fossil fuels are burnt. These particles reflect sunlight back into space or they can help produce more clouds that reflect sunlight back into space
What are 3 alternative fuels to fossil fuels?
Ethanol, Biodiesel and Hydrogen gas
Ethanol: Prodced/Made from, Uses
Can be produced from plant material ( = Biofuel) It's made by fermentation of plants and is used to power cars in some places. It's often mixed with petrol.
Advantages of Ethanol?
Carbon Neutral - The CO2 released when its burnt was taken in by the plant as it grew. The only other product is water
Disadvantages of Ethanol?
Engines need to be converted before they'll work with ethanol fuels.
Ethanol fuel isn't widely available.
There are worries that as demand for it increases farmers will switch from growing fuel crops to growing crops to make ethanol - increase in food prices
Biodiesel: Prodced/Made from, Uses
Another type of biofuel. Can be produced from vegetable oils (eg, rapeseed and soybean oil). Can be mixed with ordinary diesel fuel and to run a diesel engine
Advantages of Biodiesel?
Engines don't need to be converted
Produces much less sulfur dioxide and 'particulates' than normal petrol/diesel
Disadvantages of Biodiesel?
We can't make enough to replace diesel
Expensive to make
Could increase food prices like ethanol
Hydrogen gas: Prodced/Made from, Uses
Can be used to power vehicles.
Get the hydrogen from the electrolysis of water - there's plenty of water but it takes electrical energy to split up (this energy can come from a renewable source)
Advantages of Hydrogen gas?
Hydrogen combines with oxygen in air to form water - very clean