Year 9 IGCSE Key Terms Flashcard

acid rain
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
alkanes
a homologous series of hydrocarbons which are saturated as they have only single bonds between the carbon atoms
alkenes
a homologous series of hydrocarbons which are unsaturated as they have at least 1 double bond somewhere in the chain
alloys
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
alkali
any base which is soluble in water
anions
negative ions; attracted to anode
anode
positive electrode in electrolysis
atomic number
number of protons in the nucleus of an atom, determines the order and place of each element in the Periodic Table
catalytic converter
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
cathode
negative electrode in electrolysis
cation
positive ion ; attracted to cathode
chromatography
a separating technique which uses the difference in solubility in a given solvent between the different parts of a mixture to separate them;
combustion
burning, the reacting of a substance with oxygen, exothermic
complete combustion
combustion in sufficient oxygen which in the case of hydrocarbons produces carbon dioxide and water
compound
a pure substance made from two or more different atoms joined together chemically
condensation
a process during which a gas changes into a liquid because its particles are having less energy, slow down and come much closer together
covalent bond
force of attraction between a pair of shared electrons and the nucleii of both atoms
cracking
the breaking down of long-chain alkanes into smaller alkanes and alkenes using a catalyst and heat (500 C)
diffusion
the movement of particles by which different substances mix as a result of the random motion of each of their particles
displacement reaction
a reaction in which a more reactive metal or halogen takes the place of a less reactive metal or halogen in its compound
distillate
the liquid obtained from distillation; the liquid which has evaporated and condensed
electrolysis
a reaction which uses electricity to decompose a compound
electrolyte
an ionic compound or acid which conducts electricity (molten or in solution) and which is decomposed as it conducts
element
a pure substance that consists of 1 type of atom only
filtrate
the liquid/solution that goes through the filter paper
fraction
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);
gas
a state of matter in which particles are far apart, have a lot of energy and move fast and randomly
galvanising
the coating of steel or iron by zinc to protect it from rusting
half equation
equation showing what goes on at each electrode in electrolysis
homologous series
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.
hydrocarbon
a compound which has carbon and hydrogen only
incomplete combustion
burning in not enough oxygen
ion
a charged atom or group of atoms (which has become charged because it has either lost or gained an electron(s))
ionic bond
strong electrostatic attraction between two oppositely charged ions, formed between metals and non-metals
isotopes
atoms with the same number of protons and electrons but different number of neutrons; same mass number but different mass number
liquid
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
mass number
the total number of protons and neutrons in the nucleus of an atom
metallic bond
attraction between positive metal ions and delocalised ?sea? of electrons
mixture
2 or more substances mixed together which have not reacted and which are therefore easily separated by physical processes like evaporation/distillation/filtration
oxidation
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
oxidizing agent
a chemical which oxidises another chemical; it loses oxygen/gains electrons and becomes reduced
redox
a reaction during which both a chemical is oxidised and another is reduced
reducing agent
a chemcial which reduces another chemical; it gains oxygen/loses electrons and becomes oxidised
reduction
a reaction during which a susbstance loses oxygen and has its mass decreases; also a reaction during which a substance gains electrons
sacrificial protection
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
solid
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
solvent
a liquid that does the dissolving
solvent front
the height the solvent goes up to on the chromatography paper
solute
a solid which dissolves
solution
a mixture made by dissolving a solute in a solvent
thermal decomposition
breaking down of a compound by heating it
volatile
vapourises easily, low boiling point

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