what is in clean air? Flashcards
How much nitrogen is in the air?
78%
how much oxygen is in clean air?
21%
how much carbon dioxide is in clean air?
0.035%
Why do the percentages of gases in our air change?
because there is a balance between the processes that use up and make both carbon dioxide and oxygen
What do the arrows in the carbon cycle represent?
the direction of movement of carbon compounds
what 2 factors have caused the percentage of carbon dioxide to increase over the last few centuries?
deforestation- as more rainforests are cut down, less photosynthesis takes place
increased population- as populations increase, the worlds energy requirements increase.
Why over the last few centuries has the percentage of carbon dioxide in the air increased slightly due to 2 factors? what are they?
deforestation- as more rainforests are cut down, less photosynthesis takes place
increased population- as populations increase, the worlds energy requirements increase.
what does photosynthesis use and and create?
it uses up carbon dioxide and creates oxygen
what does respiration use up and create?
it uses up oxygen and creates carbon dioxide
what organisms respire?
plants and animals
what does combustion use up and create?
uses up oxygen and creates carbon dioxide
what is clean air?
clean air is the air that has no pollutants caused by human activity
what are the 5 main gases in the air?
nitrogen, oxygen, carbon dioxide, water vapour, and noble gases (argon neon, krypton, xenon)
what is the equation for respiration?
glucose + oxygen – carbon dioxide + water
what is the equation for photosynthesis?
carbon dioxide + water – glucose + oxygen
what do scientists know about where gases came from?
they come from the centre of the earth in a process called degassing
what formed the original atmosphere? and what do plants do to oxygen and carbon dioxide?
Gas escaping from the interior of the earth. Plants that could photosynthesise removed carbon dioxide form the atmosphere and added oxygen. Eventually the amount of oxygen reached its current level.
describe one theory about the original atmosphere?
the atmosphere was originally rich in water vapour and carbon dioxide. This vapour condensed to form oceans and the carbon dioxide dissolved in water. The percentage of nitrogen slowly increased and, little nitrogen was removed.
name one factor that made oxygen in the atmosphere increase
organisms that could photosynthesise evolved and converted carbon dioxide and water into oxygen. As the percentage of oxygen increased, the percentage of carbon dioxide decreased, until today’s levels were reached.
name one factor that made oxygen in the atmosphere increase
organisms that could photosynthesise evolved and converted carbon dioxide and water into oxygen. As the percentage of oxygen increased, the percentage of carbon dioxide decreased, until todays levels were reached.
Why is it important to control atmospheric pollution?
because of the effects it can have on peoples health, the natural environment and the built environment.
what is sulphur dioxide? and what difficulties can it cause? (2 points)
a pollutant that can cause difficulties for people with asthma. It can also dissolve in to form acid rain that damages wildlife and limestone buildings.
what does a car do fitted with a catalytic converter?
converts carbon monoxide into carbon dioxide.
what reaction takes place in a catalytic converter? what is the balanced symbol equation for this?
a reaction between nitric oxide and carbon monoxide takes place on the surface of the catalyst. 2CO + 2N0 — N 2 +2C0 2
what are pollutants?
substances made by human activity that harm the environment
what does acid rain do to the environment?
erodes stone in buildings and statues, corrodes metal and kills plants and fish
what are the main 3 pollutants in the atmosphere?
carbon monoxide, oxides of nitrogen and sulfur dioxide
what are the environmental effects of carbon monoxide?
poisonous gas is formed by incomplete combustion of petrol or diesel powered by motor vehicles
what are the environmental effects of oxides of nitrogen?
photochemical smog acid rain formed by reaction of nitrogen and oxygen at very high temperatures such as in an internal combustion engine
what are the environmental effects of sulfur dioxide?
acid rain formed from sulfur impurities when fossil fuels burn
what does a catalytic converter do?
reduces the levels of carbon monoxide and oxides of nitrogen
what gases come from a cars exhaust?
nitric oxide and carbon monoxide
what gases do catalytic converters change in a car exhaust?
carbon monoxide into carbon dioxide and at the same time oxides of nitrogen into nitrogen
what does less oxides of nitrogen reduce the risk of?
less risk of photochemical smog
what does a high temperature inside an internal combustion engine allow?and why?
nitrogen from the air to react with oxygen to make oxides of nitrogen because there is enough energy to break the strong bonds between nitrogen atoms
what do catalytic converters contain?
a rhodium catalyst
what reaction takes place on the surface of a catalyst? and what does the reaction form?
a reaction between nitrogen monoxide and carbon monoxide. The reaction forms nitrogen and dioxide
what did carbon dioxide dissolve in?
water
how did we get water from volcanoes
as the gas water vapour was made from volcanoes, the earth was cooling down which meant the water vapour could condense in the atmosphere and turn into water
