chemistry 9
what is acid rain?
rain that is adicic due to dissolved gases, such as sulfur dioxide, produced from the burning of fossil fuels
what is a carbon footprint?
the total amount of carbon dioxide and other greenhouse gases emitted over the full life cycle of a product
what is environmental implication?
the effect that the activity has on the environment
what are fossil fuels?
natural fuels such as coal and gas formed in the past from the remains of living organisms
what is global climate change?
a long- term shift in global climate patterns
what is global dimming?
a gradual reduction in the amount of light reaching the earths surface, caused by carbon particulates
what are particulates?
can cause global dimming and health problems for humans. carbon particulates (soot) are a product of incomplete combustion
what are pollutants?
a substance introduced into the environment that has undesired effects
what is the greenhouse effect?
the increase in the temperature of the earths atmosphere due to the greenhouse gases in the atmosphere trapping infra-red radiation from the surface
what are greenhouse gases?
include water vapour, carbon dioxide and methane. greenhouse gases in the atmosphere maintain temperatures on earth high enough to support life
what is the equation for photosynthesis?
carbon dioxide + water + energy = glucose + oxygen
how is carbon monoxide formed?
incomplete combustion
what is the problem of carbon monoxide?
toxic, not easily detected, colourless and odorless
how is carbon dioxide formed?
complete combustion
how are particulates formed?
incomplete combustion
what are the problems of particulates?
global dimming, asthma, may cause cancer
when does complete combustion occur?
when there is excess of oxygen
when does incomplete combustion occur?
when there is insufficient oxygen
how does sulfur dioxide form?
some fuels, especially coal, contains sulfur. this reacts with oxygen in combustion to form sulfur dioxide
what are the problems of sulfur dioxide?
causes acid rain and respiratory problems in humans
how is nitrogen oxide formed?
nitrogen and oxygen from the air react at high temperatures inside car engines
what problems does nitrogen oxide cause?
acid rain and respiratory problems in humans
what problems does acid rain cause?
lowers PH of rivers and lakes, damages buildings made of limestone or marble, makes soil acidic, kills fish and other organisms, removes minerals and adds toxic chemicals to soil so plants and trees cannot grow, kills trees- damages waxy coating on leaves, reducing photosynthesis
why is there limited evidence of earths early atmosphere?
it was 4.6 billion years ago
how did earths early atmosphere form?
initially earth was covered by volcanoes which erupted and released lots of gases
how did oceans form?
water vapour condensed to form oceans
what caused a decrease in carbon dioxide?
it dissolved in oceans forming carbonates- precipitated as sedimentary rocks, formation of fossil fuels which have carbon trapped within them, photosynthesis of algae and plants
what were the gases like in the early atmosphere?
approximately 10% nitrogen, 20% oxygen and small amounts of gases like carbon dioxide, water vapour and noble gases
what do humans do that increases the amount of greenhouse gases?
deforestation, burning fossil fuels, agriculture, landfill sites
what is thermal radiation?
long wavelength radiation reflected back by the earth
what are some consquences of climate change?
ice caps melting, higher sea levels, increased flooding, storms more extreme and frequent, changes in rainfall pattern, food production affected
how can the carbon footprint be reduced?
renewable energy resources, technologies that capture carbon dioxide before it is released, taxing companies based on carbon footprint
why is it difficult to lower the carbon footprint?
some dont want to make changes to their lifestyle, dont want to disrupt economy, government not prepared to make radical changes and alternative processes and technologies need more work