A process to change waste materials into new products to prevent waste of potentially useful materials, reduce the consumption of fresh raw materials, reduce energy usage and reduce pollution.
What is recycling.
100
The compounds which were used in refrigerators, air conditioners, blowing agents, solvents, dry cleaning agents and cause ozone depletion.
What are chlorofluorocarbons.
100
The molecule which is dissolved in rainwater which makes rainwater naturally acidic.
What is carbon dioxide.
100
The part of water treatment which involves filtration, flocculation and sedimentation.
What is primary treatment.
100
The amount of dissolved oxygen needed by aerobic biological organisms in a body of water to break down organic material present in a given water sample at certain temperature over a specific time period.
What is Biological Oxygen Demand.
200
A method of waste disposal where waste is buried in the ground.
What is landfill.
200
Regions where greater ozone depletion takes place due to cold winter temperatures and ice crystals which act as catalysts.
What are polar regions.
200
A type of acid deposition where gas molecules or acidic particles attached onto small airborne particles such as dust leave the atmosphere as they are brought back down to earth.
What is dry deposition.
200
Two methods for obtaining fresh water from sea water.
What are reverse osmosis and distillation.
200
Increase in the rate of supply of organic matter in an ecosystem which typically promotes the excessive growth of algae.
What is eutrophication.
300
A waste disposal method which involves the burning of waste.
What is incineration.
300
The reaction mechanism of the catalytic depletion of ozone by CFCs.
Hint: The reaction mechanism is made of three steps.
What is CCl2F2 = •CClF2 + Cl•
•Cl + O3 = ClO• + O2
ClO• + •O = •Cl+ O2
300
The reaction of sulphuric acid in acid rain with marble in buildings.
What is CaCO3 (s) + H2SO4 (aq) = CaSO4(s) + H2O(l) + CO2 (g)
300
The harmful effect of irrigating soils because water used for irrigation usually contains dissolved salts, which are left behind in the soil after the water evaporates.
What is salinization.
300
The anaerobic respiration product of Sulphur.
What is H2S.
400
A material that is recycled by the steps crushing, melting and remoulding.
What is glass.
400
Compounds which are alternatives to CFCs because the have an H atom which makes the molecule more stable.
What are hydrochlorofluorocarbons.
400
A two step reaction where nitric acid is formed from nitrogen monoxide and a hydroxyl radical.
What is HO+ NO→HNO2
2HNO2 + O2 → 2HNO3
400
The amount of exchangeable cations, such as K+, Ca2+ and Mg2+, that 100g of soil can hold.
What is cation exchange capacity.
400
Occurs when a layer of warm air settles over a layer of cooler air that lies near the ground. The warm air holds down the cool air and prevents pollutants from rising and scattering.
What is thermal inversion.
500
The process used to convert high level radioactive waste into glass before the waste is buried underground in granite rock.
What is vitrification.
500
The wavelength of UV light that ozone molecules absorb.
What is 290 – 320 nm.
500
The three step reaction where sulphuric acid is formed from a hydroxyl free radical and sulphur dioxide.
What is HO + SO2 → HOSO2
HOSO2 + O2 → HO2+ SO3
SO3 + H2O → H2SO4
500
The solubility product of the following system:
MX(s) = aM+ (aq) + bX- (aq)
What is Kc = [M+(aq)]a [X− (aq)]b.
500
A two step reaction in a car exhaust which causes the formation of NO2 which is a secondary pollutant.