C11 - Air and Water Flashcards
Describe the chemical test for water using cobalt (II) chloride [1]
Blue anhydrous cobalt (II) chloride turns pink in the presence of water
Describe the chemical test for water using copper (II) sulfate [1]
White anhydrous copper (II) sulfate turns blue in the presence of water
What does potable mean? [1]
Safe to drink
Describe 2 main stages required to make water potable [2]
Filtration - removes insoluble particles by passing the water through layers of sand and filters / Chlorination - kills bacteria and microorganisms which are too small to be removed by filtration
What is the percentage composition of gases in the atmosphere [4]
Nitrogen 78% / Oxygen 21% / Argon 0.93% / Carbon dioxide 0.04%
What are the three common pollutants in the air [3]
Carbon monoxide / sulfur dioxide / oxides of nitrogen
What are the sources of pollutant gases in the air? [3]
Carbon monoxide - incomplete combustion of carbon fuels / sulfur dioxide - sulfur impurities in fossil fuels / oxides of nitrogen - car engines
What conditions in car engines lead to the production of oxides of nitrogen? [1]
High temperature
What are the problems associated with carbon monoxide? [2]
Toxic gas / Prevents the red blood cells from carrying oxygen around the body
What are the problems associated with sulfur dioxide? [3]
Acid rain which causes - corrosion of limestone buildings and statues / kills aquatic life / damages and kills vegetation
What are the problems associated with oxides of nitrogen? [2]
Produces acid rain / Reacts with other pollutants to cause photochemical smog which causes respiratory problems
Describe two approaches to reducing emissions of sulfur dioxide [2]
Use of low sulfur petrol / flue gas desulfurisation by calcium oxide
Describe in equations how a catalytic converter removes oxides of nitrogen and carbon monoxide from exhaust emissions [3]
2CO + O₂ → 2CO₂ 2CO + 2NO → 2CO₂ + N₂ 2NO → N₂ + O₂
What is corrosion? [2]
Rusting of iron / in the presence of oxygen and water in the air
What two substances need to be excluded to prevent iron rusting? [2]
Oxygen / Water
How can oxygen and water be excluded to prevent iron rusting? [4]
Paint the metal / coat the metal in oil / cover the metal in plastic / keep the metal in a vacuum container
What is sacrificial protection and how does it work? [2]
Coating the metal being protected with a more reactive metal / the outer metal will corrode first and prevent the corrosion of the inner metal
What is galvanisation? [2]
Sacrificial protection or iron / using zinc
Name two major greenhouse gases [2]
Carbon dioxide / methane
Describe sources of carbon dioxide [4]
Complete combustion of carbon containing substances / product of respiration / product of the reaction between an acid and a carbonate / product of thermal decomposition of calcium carbonate
What has increased concentrations of greenhouse gases caused? [1]
Global warming
Compounds of which three elements are commonly found in fertilisers? [3]
Nitrogen / Phosphorus / Potassium
Why is nitrogen important to a plant? [1]
Chlorophyll which makes the plant green and is important for photosynthesis
Why is phosphorus important to a plant? [1]
Strong roots
Why is potassium important to a plant? [1]
Healthy growth
Describe the displacement of ammonia from its salts [2]
Ammonium salt is reacted with a strong base / ammonia is produced along with a different salt and water
Write the equation that takes place between ammonium chloride and sodium hydroxide [1]
NH₄Cl + NaOH → NaCl + NH₃ + H₂O
What is the Haber process? [1]
An industrial process to produce ammonia
What is the equation for making ammonia in the Haber process? [1]
N₂ + H₂ → 2NH₃
What conditions are used in the Haber process? [3]
450ᵒC / 200 atm pressure / iron catalyst
What is the source of hydrogen in the Haber process? [1]
Reaction of methane with steam
What is the source of nitrogen in the Haber process? [1]
From the air
