11 Air and Water Flashcards
Chemical tests for water (2)
cobalt(II) chloride (blue = anhydrous, pink = hydrous)
copper(II) sulfate (white = anhydrous, blue = hydrous)
Treatment of water supply (4 steps)
coagulation, sedimentation, filtration, chlorination
Composition of air
78% nitrogen
21% oxygen
1% noble gases, water vapour and carbon dioxide
(0.9% argon, 0.2-0.4% water vapour, 0.04% carbon dioxide)
Common pollutants of air
carbon monoxide
sulfur dioxide
nitrogen oxides
Adverse effects of common pollutants of air
carbon monoxide - binds with haemoglobin
sulfur dioxide + nitrogen oxides - get stuck in lungs, form acid rain
Sources of common pollutants of air
carbon monoxide - incomplete combustion of hydrocarbons
sulfur dioxide - combustion of fossil fuels containing sulfur compounds
oxides of nitrogen - car engines (nitrogen + oxygen in air + high temp)
Approaches to reducing emissions of sulfur dioxide (2)
use of low sulfur petrol
flue gas desulferisation by calcium oxide
Catalytic converter
removes nitrogen monoxide and carbon monoxide from exhaust emissions by reaction over hot catalyst
2CO + O2 –> 2CO2
2NO + 2CO –> N2 + 2CO2
2NO –> N2 + O2
Conditions for iron to rust (2)
water and oxygen
Barrier methods of rust prevention
paint and other coatings
Sacrificial protection (against rust)
Galvanising
reactivity series of metals
Formation of carbon dioxide
complete combustion of carbon-containing substances
respiration
acid and carbonate reaction
thermal decomposition of calcium carbonate
Greenhouse gases (2)
carbon dioxide and methane
Increased concentrations of greenhouse gases cause …
an enhanced greenhouse effect, which may contribute to climate change
Fertilisers need which 3 elements
nitrogen, phosphorus and potassium
