Global dimming The reflection of sunlight by tiny solid particles in the air
Global warming The warming of the Earth due to the reflection of infra red radiation by Greenhouse gases
Glucose The product of photosynthesis in plants and the molecule used in respiration
Graphite A carbon structure where carbon atoms are covalently bonded to three other carbons and the fourth electron is delocalised
Greenhouse effect The warming of the Earth due to the reflection of infra red radiation
Greenhouse gas A greenhouse gas is any gas that contributes to the greenhouse effect, e.g. carbon dioxide, methane and water vapour
Groups The columns in the Periodic Table, eg group 7 - the halogens
Haber process A process used to make ammonia from nitrogen and hydrogen
Haematite A rock containing iron oxide, an example of iron ore.
Half equation An equation used to show the reaction that occurs at the electrodes during electrolysis
Halogens Elements from group 7 of the Periodic Table, such as chlorine and bromine
Hard A hard material is difficult to scratch, e.g. diamond
Hard water Hard water contains ions which cause scum or limescale
Hardening During hydrogenation of vegetable oils, the hydrogenated product has been hardened so that it has a higher melting point and is more solid at room temperature.
Homologous series Alkanes, alkenes and alcohols are all examples of homologous series. They all contain the same functional group but different carbon chain lengths.
Hydrated Chemicals that have water bonded in the molecule
Hydrocarbon A compound containing only hydrogen and carbon, e.g. methane
Hydrogenated oil A polyunsaturated oil can be hydrogenated to make it more solid at room temperature. Some of the double bonds in the polyunsaturated oil are saturated oil by reacting with hydrogen in the presence of a nickel catalyst at 60 degrees C
Hydrogenation Adding hydrogen to a polyunsaturated oil in thr presence of a nickel catalyst at 60 degrees celcius. In the process some of the double bonds are saturated.