chemtistry definitions post mocks

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  • Created by: charlie
  • Created on: 19-04-14 15:14
heterolytic fission
breaking of covalent bond with both of the bonded electrons going to one of the atoms (cation + anion_
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activation energy
minimum energy required to start a reaction without breaking bonds
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addition polymerisation
process in which unsaturated alkene molecules add onto growing polymer chain to form very long saturated molecular chain (addition polymer)
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addition reaction
reactant added to unsaturated molecule to make saturated molecule
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atom economy
EQUATION...
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atomic orbital
region within an atom that can hold up to two electrons with opposite spins
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average bond enthalpy
average enthalpy change that takes place when breaking by homolytic fission 1 mol of a given type of bond in molecules of gaseous species
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bond enthalpy
enthalpy change that takes place when breaking by homolytic fission 1 mol of given bond in molecules of gaseous species
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carbocation
organic ion which a carbon atom has negative charge
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catalyst
substance that increases the rate of chemical reaction without being used up in the process
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cracking
breaking down of long-chained saturated hydrocarbons to form mixture of shorter chained alkanes + alkenes
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delocalised electron
electrons shared between more than 2 atoms
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displacement reaction
reaction which more reactive element displaces a less reactive element from an aqueous solution of the latter's ions
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dynamic equilibrium
equilibrium that exists in a closed system when the rate of the forward reaction is equal to the reverse reaction
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E/Z isomerism
type of stereoisomerism which different groups attached to each carbon of C=C bond may be arranged differently in space due to restricted rotation of C=C bond
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electron shielding
repulsion between electrons in different inner shells reducing net attraction from +ve nucleus on outer electron
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electrophile
atom(s) attracted to electron-rich centre or atom where it accepts a pair of electrons to form a new covalent bond
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endothermic reaction
reaction where enthalpy of product > enthalpy of reactants (results in heat being taken from surroundings)
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(standard) enthalpy change of reaction
enthalpy change that accompanies a reaction in the molar quantities expressed in a chemical equation under standard conditions reactants and products in standard states
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exothermic
enthalpy of product < enthalpy of reactants (heat loss to surroundings)
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fractional distillation
separation of components in a liquid mixture into fractions which differ in boiling points
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fragmentation
process in mass spectrometry that causes +ve ion to spilt into pieces (one of which is +ve fragment ion)
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giant covalent / ionic / metallic lattice
3-d structure of atoms bonded by strong covalent bonds / of opposite charge ions bonded by strong ionic bonds / of +ve ions and delocalised electrons bonded by strong metallic bonds
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greenhouse effect
absorbtion + subsequent emission of infrared radiation by atmospheric gases warms the lower atmosphere + planet surface
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heterogeneous catalysis
catalyst has a different physical state from reactants; frequently reactants are gases + catalysts solid
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homogenous catalysis
catalyst + reactants in same physical state (most frequently gaseous or aqueous)
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homolytic fission
breaking of covalent bond with one of bonded electrons going to each atoms (forms radicals)
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(successive) ionisation energy
measure of energy required to remove each electron in turn
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le Chatelier's principle
when a system is in dynamic equilibrium its subject to change, position of equilibrium will shift to minimise the change
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nucleophile
atom(s) attracted to electron-deficient centre or atom, where it donates a pair of electrons to form new covalent bond
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nucleophilic substitution
substitution reaction in which nucleophile attracted to electron-deficient centre or atom, where it donates a pair of electrons to form new covalent bond
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percentage yield
EQUATION...
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radical
species with unpaired electron
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rate of reaction
change in concentration of a reactant or product in a given time
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salt
chemical compound formed from acid, when H + ion from the acid replaced by metal ion or +ve ion (e.g. NH4+)
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shell
group of atomic orbitals with same principal quantum number (main energy level)
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specific heat capacity
energy required to raise temperature of 1g of substance by 1
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sub-shell
group of same type of atomic orbitals (S,P,D,F) within a shell
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volatility
ease with which a liquid turns into a gas (volatility increases as boiling point decreases)
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Other cards in this set

Card 2

Front

minimum energy required to start a reaction without breaking bonds

Back

activation energy

Card 3

Front

process in which unsaturated alkene molecules add onto growing polymer chain to form very long saturated molecular chain (addition polymer)

Back

Preview of the back of card 3

Card 4

Front

reactant added to unsaturated molecule to make saturated molecule

Back

Preview of the back of card 4

Card 5

Front

EQUATION...

Back

Preview of the back of card 5
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