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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?

Carbon dioxide
- deforestation
- 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
Energy conservation
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
Lifestyle changes
Economic considerations
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

Rechargeable cells
Non rechargeable cells
Fuel 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


Disadvantages of hydrogen fuel cells

Hydrogen is highly flammable
Hydrogen is difficult to store
Hydrogen sometimes produced by non renewable resources