Flashcards in Module 2 Deck (28):
What are the proportions of gases in the atmosphere today?
Nitrogen - 80%
Oxygen - 20%
Carbon dioxide, water vapour and methane - small proportions
Why has oxygen increased in the atmosphere?
Photosynthesis, plants release oxygen and reduce the amount of carbon dioxide
How has the level of nitrogen increased in the atmosphere?
Nitrogen is very inreactive so doesn't react with substances and volcanoes produced nitrogen
Name 3 processes that reduce carbon dioxide
Large amounts dissolved in oceans
Locked away in fossil fuels
Locked inside limestone
What are the greenhouse gases?
Water vapour, carbon dioxide and methane
What do greenhouse gases do?
They maintain temperature on earth high enough to support life
What do greenhouse gases do?
They allow short wavelength radiation to pass through the atmosphere to the earth's surface but absorb the long wavelength radiation from the earth causing the an increase in temperature
What human activities increase the amount of greenhouse gases?
- combustion of fossil fuels
- animal farming
- decomposition of landfills
What are the potential effects of global climate change?
Sea levels will rise which cause flooding and coastal erosion
More frequent severe storms
Changes the amount of distribution of rain
Temperature and water stress for humans and dwildlife
Changes to distribution of wildlife species
Changes in food producing capacity of some regions
What gases are released into the atmosphere when a fuel is burned?
Carbon dioxide, water vapour, carbon monoxide, soldier dioxide and oxides of nitrogen
What is acid rain?
Rain with a pH of 5.6 or lower its caused by pollutants sulcus dioxide and nitric oxides
Why is carbon monoxide not easily detected?
It is a colourless and odourless toxic gas, it combines with haemoglobin in the blood reducing he capacity to carry oxygen
What are particulates?
They cause global dimming, reducing the sunlight that reaches the earth's surface they cause health problems such as damage to the lungs
What is the carbon footbprint?
The total amount of carbon dioxide and other greenhouse gases emitted over the life cycle of a product, service or event
What can you do to reduce your carbon footprint?
Alternative energy supplies
Carbon capture and storage
Carbon taxes and licenses
Carbon off setting including tree planting
Carbon neutrality- zero net release
What are the problems of reducing carbon footprint?
Lack of public information and education
Incomplete international co operation
Scientific disagreement over cause and consequences of global climate changes
What is an exothermic reaction?
They transfer energy to the surroundings so the temperature of surroundings increase
E.g. Hand warmers
What is an endothermic reaction?
Is one that takes in energy from surroundings so the temperature surroundings decreases
E.g. Ice packs
What is bendomex?
Breaking bonds is ending
Making bonds is exo
What is activation energy?
The minumum amount of energy needed for a chemical reaction to take place
What are cells?
Cells contain chemicals which react to produce electricity
How can a simple cell be made?
By connecting 2 different metals in contact with an electrolyte
What are batteries?
Two or more cells connected together in series to provide a greater voltage
Name 3 types of cells
Non rechargeable cells
What is a cathode?
Negative electrode, hydrogen is supplied as fuel
What is an anode?
Positive electrode , oxygen if supplied to electrode
Advantages of hydrogen fuel cells
No pollutants produced
Can be a range of sizes
Don't have to be electrically charged