air and water

• The chemical test for water uses cobalt (II) chloride, which turns pink in the presence of water.
• Methane gas is a greenhouse gas that is produced from various sources such as combustion of fossil fuels, decomposition of vegetation, and waste gas from digestion in livestock.
• The chemical test for water uses copper (II) sulfate, which turns blue in the presence of water.
• Humans need safe drinking water that contains low levels of dissolved salts and microbes.
• Inadequate water supplies are unsafe to drink and also affect crop yield.
• Potable means safe to drink.
• Filtration and chlorination are the two main stages required to make water potable.
• Water is used in the home for drinking, cooking, plumbing, heating, and dishwashing.
• In industry, water is used as a solvent, coolant, and for washing/cleaning.
• The percentage composition of gases in the atmosphere is 78% Nitrogen, 21% Oxygen, 0.93% Argon, and 0.04% Carbon dioxide.
• Oxygen and nitrogen can be separated from liquid air using fractional distillation.
• Common pollutants in air include Carbon monoxide, Sulfur dioxide, Oxides of nitrogen, and Lead compounds.
• Pollutant gases in the air can be sourced from incomplete combustion of carbon containing compounds, combustion of fossil fuels which contain sulfur, car engines, and leaded petrol.
• Conditions in car engines that lead to the production of oxides of nitrogen include high temperature and pressure.
• Catalytic converters are fitted in cars to remove oxides of nitrogen and catalyse the reaction between carbon monoxide and nitrogen monoxide, forming nitrogen and carbon dioxide.
• To prevent rusting, oxygen and water need to be excluded, which can be done by painting the metal, coating it in oil/grease, covering it in plastic, or keeping it in a vacuum container.
• Sacrificial protection involves coating the metal being protected with a more reactive metal, so the outer metal will corrode first and prevent the corrosion of the inner metal.
• Galvanisation is the sacrificial protection of iron using zinc.
• Pollution is a global concern because fossil fuels are used globally and these pollutants are largely found all over the world.
• The reaction that takes place in a catalytic converter involves the conversion of carbon monoxide and nitrogen monoxide into carbon dioxide and nitrogen.
• The metal used for protection in sacrificial protection must be higher up the reactivity series than the other metal so that it is more reactive and will corrode first.
• Carbon monoxide is a toxic gas that is colourless and odourless and if breathed in can cause death by preventing the red blood cells from carrying oxygen around the body.
• Compounds of nitrogen, phosphorus, and potassium are commonly found in fertilisers because they improve agricultural production and these compounds are absorbed by the plants roots to help growth and development.
• Rusting is the corrosion of iron when it reacts to oxygen and water in the air.
• Lead is toxic and causes health issues if ingested.
• Sulfur dioxide combines with water vapour in the clouds to form acid rain, which causes corrosion of limestone buildings and statues, lowers the pH of large bodies of water, and damages and kills vegetation.
• Oxides of nitrogen produce acid rain with similar effects as SO2 and react with other pollutants to form a smog which causes respiratory problems.
• When an ammonium salt is reacted with a strong base, ammonia is produced along with water and a different salt.
• The greenhouse gases cause the greenhouse effect which contributes to climate change by absorbing electromagnetic radiation from the sun, radiating heat from the Earth as infrared radiation, and warming up the atmosphere further.
• The carbon cycle involves CO2 being produced during respiration and combustion, absorbed during photosynthesis to make carbohydrates in plants, released as carbon dioxide when animals respire, and released during decomposition.
• The steps in the Haber process are: obtain hydrogen and nitrogen from natural gas (or steam) and air, compress the gases to 200 atm and heat them to 450 o C, pump the gases into a tank containing layers of catalytic iron beads, nitrogen and hydrogen react to form ammonia, ammonia and any unreacted hydrogen and nitrogen pass into a cooling tank, ammonia is collected as a liquid, and the unreacted hydrogen and nitrogen are recycled back into the tank.
• Greenhouse gases are responsible for maintaining the Earth’s temperature so that life can survive, with common examples including Carbon dioxide, methane and water vapour.
• Ammonia can be produced from an ammonium salt by a displacement reaction.
• The global effects of climate change include rising sea levels, crops unable to grow, extinction of species, more extreme weather, and higher risks of skin cancer due to increased exposure to harmful UV rays.
• The Haber process is an industrial process used to produce ammonia (for fertilisers).
• The chemical equation for the reaction that takes place in the Haber process is: 3H2 + N2 ⇌ 2NH3.
• Carbon dioxide can be produced through complete combustion of carbon containing compounds, thermal decomposition of a carbonate, reaction between an acid and a carbonate, and product of respiration.
• The conditions used for the Haber process include a temperature of 450 o C, a pressure of 200 atm, and the use of an iron catalyst.