Air and Water (C11) Flashcards
(18 cards)
What are the 3 tests for water
Blue cobalt (II) chloride paper: chemical type of test : blue to pink Anhydrous copper (II) sulphate powder: chemical: white powder to blue crystals Test melting and boiling point: physical: m.p at 0, b.p at 100 degrees celsius
How is water purified
Water is pumped into screens, which remove solid floating debris
Aluminum sulphate is added to coagulate (stick together) small pieces of clay so that they are easily removed
The water is then filtered through coarse sand to remove larger, insoluble debris
The water encounters more flocculants (chemicals that make particles move down to bottom of tank) and is filtered again through fine sand
Chlorine gas is bubbled through the water to kill bacteria. This makes the water slightly acidic, so to reverse this appropriate amounts of sodium hydroxide (alkali) is added
Name 4 uses of water at home and 3 uses in industry
Home: Drinking Cooking Washing Farms
Industry:
Dissolve
Wash and cool things
Power stations where steam is used to turn turbines
Name the percentage of different components in the air
Clean air:
79% nitrogen
20% oxygen
Remainder: noble gases/water vapour/carbon dioxide
Name 4 pollutants, its source, and problems caused in air
Carbon monoxide (Co): incomplete combustion of carbon-containing substances: reacts with haemoglobin and prevents it from carrying oxygen (death to lack of oxygen)
Sulphur dioxide (So2): combustion of fossil fuels that contain sulphur: irritates eyes/throat/causes respiratory problems and acid rain
Oxides of nitrogen (NOx): car exhausts: respiratory problems and acid rain
Lead compounds: burning of petrol: damage to brain and nerve cells in young children
Name 3 sources of methane
Oil and natural gas
Decomposition of vegetation
Waste gases from digestion in animals
What is a catalytic convertor
Catalyses reduction of No2 to nitrogen gas (N2) and catalyses the oxidation of CO to CO2
Combustion engine, insufficient amounts of oxygen leads to incomplete combustion of the carbon containing fuel
What gases are produced in a catalytic convertor
Carbon monoxide
Oxides of nitrogen
Name 2 ways of rust prevention
Coating - plastic/paint/grease - electroplating with tin/chromium - galvanising: dipping in molten zinc Sacrificial protection: attaching a piece of metal that is more reactive than iron and it will corrode instead of iron (magnesium/zinc)
Why are fertilisers used
Nitrogen: chlorophyll and other proteins
Phosphorus: helps roots grow and crops ripen
Potassium: makes proteins and resists diseases
All alkali (except ammonia) will react with ammonium compounds and removing it
What are the 2 greenhouse gases
Carbon dioxide
Methane
What are greenhouse gases
Stops heat escaping into sapce
Too much leads to climate change
What are the causes of climate change
Ice poles to melt Rising sea levels More droughts Storms Floods and famine Global warming
How is carbon dioxide produced
Carbon or any of its compounds are completely burned in excess oxygen
Formed as a product of respiration
Product of reaction between acid and carbon
From thermal decomposition of a carbonate
What is the Haber Process
Industrial manufacture of ammonia (NH3)
Reversible reaction
N2 + 3H2 2NH3
What are the raw materials of Haber Process
Nitrogen: air
Hydrogen: methane + steam -> carbon dioxide + hydrogen
What are the 3 essential conditions of the Haber Process
Temperature: 450 degrees celsius
Pressure: 200 atm
Catalyst: iron
What is the Carbon Cycle
Carbon is exchanged among the different atmospheres of the Earth
