Year 10 IGCSE Key Terms

any substance that produces hydrogen ions, H+, when dissolved in water
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
activation energy
minimum amount of energy needed to start the reaction/for a successful collision.
actual yield
the amount of product obtained when carrying out a reaction
addition reaction
a reaction in which atoms are added to an unsaturated carbon compound; the atoms are added using the double bond as one of the double bonds breaks and is used to make two new bonds, e.g. alkenes and halogens
addition polymer
polymer formed by addition polymerization; adding many unsaturated monomers using double bonds
a homologous series of organic compounds which has -OH as its functional group; ethanol is a member of this homologous series
a homologous series of hydrocarbons which are saturated as they have only single bonds between the carbon atoms
a homologous series of hydrocarbons which are unsaturated as they have at least 1 double bond somewhere in the chain
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
any base which is soluble in water
negative ions; attracted to 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
a substance which can neutralise an acid to make a salt and water examples: metal oxides, metal hydroxides,
a substance which speeds up a reaction but which remains unchanged at the end of the reaction
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
negative electrode in electrolysis
positive ion ; attracted to cathode
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
a pure substance made from two or more different atoms joined together chemically
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
the breaking down of long-chain alkanes into smaller alkanes and alkenes using a catalyst and heat (500 C)
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
can easily be drawn into wires, what metals are
a reaction which uses electricity to decompose a compound
an ionic compound or acid which conducts electricity (molten or in solution) and which is decomposed as it conducts
a pure substance that consists of 1 type of atom only
empirical formula
the formula which gives the most simple ratio of atoms/ions in a molecule/formula unit
is reached when the forward reaction and reverse reaction are going on at the same time; at this point the amount of reactant or product does not change.
half equation
equation showing what goes on at each electrode in electrolysis
any element from group 7 in the Periodic table
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.
a compound which has carbon and hydrogen only
incomplete combustion
burning in not enough oxygen
any chemical which can change colour when added to different chemicals, usually acids and bases
intermolecular forces
weak forces of attraction between molecules
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
atoms with the same number of protons and electrons but different number of neutrons; same mass number but different mass number
easily shaped without breaking, what metals are
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
the name given to a certain number and that number is 6.02 x 10^23.
a particle made up of 2 or more atoms held together by covalent bonds
a small molecule which can be joined together to make a long molecule called a polymer; a monomer must have a double bond or a functional group at either end
% yield
the actual yield expressed as percentage of the theoretical yield
horizontal row in the Periodic Table
a large molecule made from many small molecules that have been joined together; each polymer is made up of many repeated units
a reaction between 2 salt solutions which produces an insoluble salt which sinks to the bottom of the test tube
insoluble solid formed during a reaction
rate of a reaction
amount of change in a reactant or product over a period of time; tells us how fast a reaction is going
relative atomic mass
the mass of an atom as compared to 1/12th of the mass of a carbon-12 atom; it is also the average mass of all isotopes
relative molecular mass
the sum of the relative atomic masses (multiplied by the number of times they are in the molecule) of the atoms in the molecule
relative formula mass
the sum of the relative atomic masses (multiplied by the number of times they are in the formula) of the atoms or ions in the giant structure
simple molecular substance
substance made up of individual molecules held together by covalent bonds and has weak intermolecular forces between these molecules
theoretical yield
the amount of product you should obtain according to the balanced equation and calculations
thermal decomposition
breaking down of a compound by heating it
vapourises easily, low boiling point

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