Year 9 IGCSE Key Terms – Flashcards
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| acid rain |
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| rain with a pH less than 5.6; acid rain has been made more acidic than normal rain because sulfur oxides and nitrogen oxides have dissolved in it; acid rain causes damage to buildings made from limestone, damages metal structures, kills fish, damages leaves in trees so they photosynthesise less |
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| alkanes |
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| a homologous series of hydrocarbons which are saturated as they have only single bonds between the carbon atoms |
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| alkenes |
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| a homologous series of hydrocarbons which are unsaturated as they have at least 1 double bond somewhere in the chain |
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| alloys |
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| mixture of a metal and small amounts of other metals and non-metals, made to have certain improved properties eg harder, stronger, increased resistance to corrosion, increased heat or electrical resistance |
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| alkali |
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| any base which is soluble in water |
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| anions |
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| negative ions; attracted to anode |
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| anode |
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| positive electrode in electrolysis |
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| atomic number |
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| number of protons in the nucleus of an atom, determines the order and place of each element in the Periodic Table |
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| catalytic converter |
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| a piece of equipment which is part of the exhaust of a car and which changes nitrogen oxides into nitrogen before they are released into the atmosphere |
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| cathode |
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| negative electrode in electrolysis |
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| cation |
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| positive ion ; attracted to cathode |
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| chromatography |
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| a separating technique which uses the difference in solubility in a given solvent between the different parts of a mixture to separate them; |
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| combustion |
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| burning, the reacting of a substance with oxygen, exothermic |
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| complete combustion |
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| combustion in sufficient oxygen which in the case of hydrocarbons produces carbon dioxide and water |
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| compound |
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| a pure substance made from two or more different atoms joined together chemically |
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| condensation |
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| a process during which a gas changes into a liquid because its particles are having less energy, slow down and come much closer together |
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| covalent bond |
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| force of attraction between a pair of shared electrons and the nucleii of both atoms |
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| cracking |
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| the breaking down of long-chain alkanes into smaller alkanes and alkenes using a catalyst and heat (500 C) |
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| diffusion |
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| the movement of particles by which different substances mix as a result of the random motion of each of their particles |
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| displacement reaction |
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| a reaction in which a more reactive metal or halogen takes the place of a less reactive metal or halogen in its compound |
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| distillate |
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| the liquid obtained from distillation; the liquid which has evaporated and condensed |
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| electrolysis |
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| a reaction which uses electricity to decompose a compound |
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| electrolyte |
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| an ionic compound or acid which conducts electricity (molten or in solution) and which is decomposed as it conducts |
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| element |
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| a pure substance that consists of 1 type of atom only |
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| filtrate |
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| the liquid/solution that goes through the filter paper |
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| fraction |
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| a group of substances which has a specific boiling point/range/condenses at similar temperature (because they have a similar number of carbon atoms in them); |
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| gas |
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| a state of matter in which particles are far apart, have a lot of energy and move fast and randomly |
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| galvanising |
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| the coating of steel or iron by zinc to protect it from rusting |
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| half equation |
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| equation showing what goes on at each electrode in electrolysis |
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| homologous series |
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| a group of organic compounds which all have the same general formula, similar chemical properties because they have the same functional group, have a gradual trend in physical properties, and differ by one CH2 unit. |
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| hydrocarbon |
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| a compound which has carbon and hydrogen only |
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| incomplete combustion |
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| burning in not enough oxygen |
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| ion |
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| a charged atom or group of atoms (which has become charged because it has either lost or gained an electron(s)) |
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| ionic bond |
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| strong electrostatic attraction between two oppositely charged ions, formed between metals and non-metals |
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| isotopes |
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| atoms with the same number of protons and electrons but different number of neutrons; same mass number but different mass number |
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| liquid |
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| a state of matter in which particles are close together but in a disorderly arrangement, they can move past one another and have energy to move from their positions |
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| mass number |
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| the total number of protons and neutrons in the nucleus of an atom |
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| metallic bond |
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| attraction between positive metal ions and delocalised ?sea? of electrons |
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| mixture |
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| 2 or more substances mixed together which have not reacted and which are therefore easily separated by physical processes like evaporation/distillation/filtration |
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| oxidation |
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| a reaction during which a substance gains oxygen; oxygen is added to the element or compound increasing its mass; also a reaction during which a substance loses an electron |
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| oxidizing agent |
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| a chemical which oxidises another chemical; it loses oxygen/gains electrons and becomes reduced |
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| redox |
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| a reaction during which both a chemical is oxidised and another is reduced |
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| reducing agent |
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| a chemcial which reduces another chemical; it gains oxygen/loses electrons and becomes oxidised |
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| reduction |
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| a reaction during which a susbstance loses oxygen and has its mass decreases; also a reaction during which a substance gains electrons |
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| sacrificial protection |
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| method of rust protection in which blocks of more reactive metal are attached to iron; the more reactive metal react with the air and water instead of the iron |
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| solid |
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| a state of matter in which particles are close together and in a regular arrangement, can only vibrate in fixed positions and have little energy |
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| solvent |
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| a liquid that does the dissolving |
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| solvent front |
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| the height the solvent goes up to on the chromatography paper |
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| solute |
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| a solid which dissolves |
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| solution |
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| a mixture made by dissolving a solute in a solvent |
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| thermal decomposition |
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| breaking down of a compound by heating it |
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| volatile |
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| vapourises easily, low boiling point |
