C6 Flashcards
what are some air pollutatnts
CO2, CO, particulates, CH4, oxides of nitrogen, SO
what are the adverse effects of CO2
increased levels lead to increased global warming, which leads to climate change
what are the adverse effects of CO
toxic gas when breathed in, causes respiratory problems and cancer
what are the adverse effects of particulates
increased risk of respiratory problems and cancer
what are the adverse effects of CH4
increased levels lead to increased global warming, which leads to climate change
what are the adverse effects of the oxides of nitrogen
acid rain and respiratory problems
what are the adverse effects of SO2
acid rain
what are the main greenhouse gases and how do they cause global warming
CO2 and CH4 absorb infrared radiation reflected & emitted by earth’s surface. the trapped heat warms the atmosphere
how is acid rain formed
rainwater is naturally acidic because CO2 in atmosphere from natural processes (eg respiration) dissolves in rainwater to form carbonic acid.
what are the acids that contribute to acid rain and how are they formed
H2SO4 and H2SO3 come from SO2, which is produced from sulphur in fossil fuels when they undergo combustion
HNO3 and HNO2 come from nitrous oxides, which are produced when nitrogen & oxygen from atmosphere react in hot car engine
how does flue gas desulphurisation reduce acid rain
- remove SO2 from exhaust gases
- scrub flue gases with limestone, SO2 react, from water, CO2, CaSO4
- process reduces release of SO2 into atmosphere, thereby reducing acid rain formation
how does low-sulphur fuel reduce acid rain
- low sulphur petrol contains less sulphur content compared to conventional petrol
- when burned in vehicles, produces less SO2 emissions
- decreased release of SO2 into atmosphere, less contribution to acid rain formation
what are the strategies to reduce the effects of climate change
- planting trees
- reduction in livestock farming
- decreasing use of fossil fuels
- increasing use of hydrogen and renewable energy, eg wind, solar
explain how planting trees will reduce the effects of climate change
trees reduce CO2 (greenhouse gas) through photosynthesis
explain how a reduction in livestock farming will reduce the effects of climate change
livestock produces a lot of methane, reduction in methane will decrease greenhouse effect
explain how decreasing use of fossil fuels will reduce the effects of climate change
- combustion of fossil fuels contributes significantly to excess CO2 in atmosphere, major greenhouse gas
- reducing use of fossil fuels will reduce CO2 released
- fossil fuels are finite resources, meaning they will eventually be depleted with continued use
explain how increasing use of hydrogen and renewable energy will reduce effects of climate change
- renewable energy sources are continuously replenished and will not run out
- will not emit as much CO2
- using hydrogen as an alternative fuel source will not produce any CO2, produce water instead
how does the ease in extracting metals from their ores relate to their position in the reactivity series
the more reactive a metal is, the harder it is to break down their metal compounds
how is iron from hermatite extracted
reduction of iron(III) oxide in a blast furnace
what is the main ore of aluminium and how is it extracted
the main ore is bauxite, it is extracted by electrolysis
how is zinc extracted from zinc blende
similar to iron (III) oxide, in a blast furnace
what is collision theory
- particles collide with each other due to chaotic, random movement
- if they collide with enough KE, a reaction will occur
- Ea (activation energy) is the min energy colliding particles must have to react
- no reaction happens if particles do not collide or collide with <Ea
- greater frequency of collisions = greater rate of reaction
what are the factors affecting rate of reaction
- surface area of solids
- concentration of solution
- pressure of gases
- temperature
- presence of a catalyst
how does changing the surface area of solids affect the rate of reaction and why
- exposes more of solid reactant’s particles to other reactant
- chance of collision increases, frequency of successful collisions increases, so rate of reaction increases
how does changing the concentration of solutions affect the rate of reaction and why
- number of particles in a given volume increases, so more chances of successful collisions and rate of reaction increased
- if solution in excess, rate of reaction directly proportional to concentration
how does changing the pressure of gases affect the rate of reaction and why
- increasing pressure similar to concentration
- by decreasing volume, number of particles per unit volume also increased
- frequency of successful collisions increased, so rate of reaction also increased
how does changing the temperature affect the rate of reaction and why
- increase in temperature increases frequency of collisions (as increased KE)
- proportion of particles with activation energy or more increases
- greatly increases frequency of successful collisions, so rate of reaction increases
how does the presence of a catalyst affect the rate of reaction and why
- catalysts work by decreasing Ea
- greater proportion of reactants particles have min energy required for successful collision, so frequency of successful collisions and rate of reaction increases
what type of reaction is this
exothermic
what type of reaction is this
endothermic
how do you know if a reaction is endothermic or exothermic
when bonds are broken, energy is required so it is an endothermic reaction
when bonds are formed, energy is released so it is an exothermic reaction
