C10 chemistry of the environment Flashcards
tests for water
cobalt(II) chloride
copper(II) sulfate
describe test for water using cobalt(II) chloride
- when anhydrous, it is blue
- when exposed to water, changes to pink
describe test for water using copper(II) sulfate
- white in anhydrous
- when exposed to water, changes from white to blue
fixed points of pure vs impure substances
pure: exact fixed points
impure: range of temperatures for change of state
why is distilled water used in practical chemistry rather than tap water
contains fewer chemical impurities
describe the treatment of domestic water supply
- sedimentation and filtration to remove solids
- use of carbon to remove tastes and odours
- chlorination to kill microbes (pathogens)
composition of air
- 78% nitrogen
- 21% oxygen
- mixture of noble gases and carbon dioxide
source of carbon dioxide as an air pollutant
complete combustion of carbon-containing fuels
source of carbon monoxide and particulates as an air pollutant
incomplete combustion of carbon-containing fuels
source of methane as an air pollutant
- decomposition of vegetation
- waste gases from digestion in animals
source of oxides of nitrogen as an air pollutant
car engines
source of sulfur dioxide as an air pollutant
combustion of fossil fuels which contain sulfur compounds
adverse effects of carbon dioxide (air pollutant)
- higher levels of CO2
- increased global warming
- leads to climate change
adverse of carbon monoxide (air pollutant)
toxic gas
adverse effects of methane (air pollutant)
- increased global warming
- leads to climate change
adverse effects of oxides of nitrogen (air pollutant)
- acid rain
- respiratory problems
adverse effects of sulfur dioxide (air pollutant)
acid rain
state strategies to reduce effects of climate change
- planting trees
- reduction in livestock farming
- decreasing use of fossil fuels
- increase use of hydrogen and renewable energy
strategies to reduce effects of acid rain
- reduce emissions of sulfur dioxide by using low-sulfur fuels
- flue gas desulfurisation with calcium oxide
how are oxides of nitrogen produced (pollutant)
- car engines
- very hot, nitrogen and oxygen from air react tg at high temp
how are oxides of nitrogen removed (pollutant)
- catalytic converters
- catalyse reaction between carbon monoxide and nitric oxide
2Co + 2NO –> 2CO2 + N2
how does flue gas desulfurisation work
- waste gases called flue gases
- passed over calcium oxide
CaO + SO2 –> CaSO3
how does planting trees reduce the effects of climate change
- absorb carbon dioxide for photosynthesis
- remove from atmosphere and store in carbon compounds ef wood
how does a reduction in livestock farming reduce the effects of climate change
- released large quantities of methane because of digestive processes (particularly cattle)
explain how decreasing the use of fossil fuels reduces the effects of climate change
- reduce quantities of carbon dioxide released
- eg walking/cycling instead of car
- replacement sources of energy needed
explain how increasing the use of renewable energy reduces the effects of climate change
- can be replaced as they are used and will not run out
- eg wind energy, solar energy
explain how increasing the use of hydrogen reduces the effects of climate change
- alternative fuel that doesn’t release CO2 when burned
- only a helpful replacement if obtained using renewable energy sources, eg electrolysis of water
describe how the greenhouse gases cause global warming
- thermal energy from sun enters atmosphere
- some absorbed by surface, some reflected and emitted back to space
- greenhouse gases absorb some thermal energy, reflect some back to earth
- reduces thermal energy loss to space
