Module 2 Definitions

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Empirical Formula
A formula which shows the simplest whole number ratio of atoms of each element in a compound
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Molecular Formula
A formula which shows the actual number of atoms of each element in a molecule
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Molar Gas Volume
The volume of one mole of gas under specified conditions of temperature and pressure e.g. 24dm3 at 20oC and q atmosphere pressure
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Percentage yield
Actual yield/theoretical yield x100
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Atom Economy
Mass of desired product/total mass of products x100
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Homologous Series
Compounds which have the same general formula, similar chemical properties, show a gradation in physical properties and successive members differ by a CH2 unit
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Functional Group
Reactive group within a compound
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Structural Isomers
Molecules which have the same molecular but a different structural formula
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Geometric Isomers
Molecules with the same structural formula, but different arrangement of atoms due to the presence of one or more C=C bond
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Saturated Hydrocarbon
Contains no C=C or C≡C bond
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Hydrocarbon
Contains hydrogen and carbon only
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Substitution
Replacing one atom or group with a different atom or group
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Homolytic fission
Bond breaking in which one of the shared electrons goes to each atom
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Heterolytic
Bond breaking in which both electrons in the shared pair go to a single atom
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Radical
A particle with an unpaired electron
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Unsaturated Hydrocarbon
Contains at least one C=C or C≡C bond
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Sigma Bond
A covalent bond formed by the linear overlap of atomic orbitals
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Pi bond
A covalent bond formed by the sideways overlap of p orbitals
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Bond Length
The distance between the nuclei of 2 covalently bonded atoms
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Hydrogenation
Addition of a hydrogen molecule across a C=C
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Electrophile
An ion or molecule that attacks regions of high electron density
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Primary Carbocation
A carbocation which has one carbon atom directly bonded to the positively charged carbon
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Secondary Carbocation
A carbocation which has 2 carbon atoms directly bonded to the positively charged carbon
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Tertiary Carbocation
A carbocation which has 3 carbon atoms directly bonded to the positively charged carbon
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Polymerisation
Joining together of many small molecules to form a large molecule
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Monomers
Many small molecules which join together to form a polymer
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Polymer
A large molecule formed when monomers join together
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Primary Halogenoalkane
A halogenoalkane which has one carbon atom directly bonded to the carbon atom that is bonded to the halogen
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Secondary Halogenoalkane
A halogenoalkane which has 2 carbon atoms directly bonded to the carbon that is bonded to the halogen
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Tertiary Halogenoalkane
A halogenoalkane which has 3 carbon atoms directly bonded to the carbon atom that is bonded to the halogen
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Reflux
Repeated boiling and condensing of a mixture
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Hydrolysis
Breaking up molecules by reaction with water
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Necleophile
An ion or molecule, with a lone pair of electrons, that attacks regions of low electron density
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Elimination
A reaction in which a small molecule is removed from a larger molecule
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Miscibility
Liquids which mix in all proportions e.g. form a single layer
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Primary Alcohol
An alcohol which has one carbon atom directly bonded to the carbon atom that is bonded to the -OH group
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Secondary Alcohol
An alcohol which has 2 carbon atoms directly bonded to the carbon atom that is bonded to the -OH group
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Tertiary Alcohol
An alcohol which has 3 carbon atoms directly bonded to the carbon atom that is bonded to the -OH group
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Ground state (IR spec)
A molecular vibration which is in the lowest possible energy state
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Wave number
The reciprocal of the wavelength, measured in cm-1
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Endothermic
A reaction in which the enthalpy of the products is greater than the enthalpy of the reactants
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Exothermic
A reaction in which the enthalpy of the products is less than the enthalpy of the reactants
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Standard conditions
298K and 100kPa
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Standard enthalpy change
Change in heat energy at constant pressure, measured at standard conditions
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Standard enthalpy of combustion
The enthalpy change when one mole of a substance is completely burnt in oxygen under standard conditions
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Standard enthalpy of formation
The enthalpy change when one mole of a compound is formed from its elements under standard conditions
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Standard enthalpy of neutralisation
The enthalpy change when one mole of water if produced in a neutralisation reaction under standard conditions
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Conservation of energy
Energy cannot be created or destroyed but it can change from one form to another
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Hess's Law
The enthalpy change for a reaction is independent of the route taken, provided the initial and final conditions are the same
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Average bond enthalpy
The energy required to break one mole of a given bond averaged over many compunds
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Reaction rate
The change of the concentration (amount) of a reactant or product with respect to time
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Catalyst
A substance which increases the rate of a chemical reaction but does not get used up
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Activation energy
The minimum amount of energy required for a reaction to occur
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Reversible
A reaction which goes in both the forward and backward direction
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Dynamic (equilibria)
Rate of forward reaction is equal to the rate of backward reaction
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Equilibrium
A reversible reaction in which the amount of each reactant/ product remains is constant
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Homogeneous
A reaction in which all the reactants and products are in the same physical state
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Heterogeneous (equilibria)
reaction in which all the reactants and products are not in the same physical state
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Heterogeneous (catalyst)
The catalyst is in a different phase from the reactants
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S-block element
An atom which has an atom with highest energy/ outer electron in an s-subshell
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Solubility
The maximum mass of solute that will dissolve in 100g of solvent at a stated temperature
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Other cards in this set

Card 2

Front

A formula which shows the actual number of atoms of each element in a molecule

Back

Molecular Formula

Card 3

Front

The volume of one mole of gas under specified conditions of temperature and pressure e.g. 24dm3 at 20oC and q atmosphere pressure

Back

Preview of the back of card 3

Card 4

Front

Actual yield/theoretical yield x100

Back

Preview of the back of card 4

Card 5

Front

Mass of desired product/total mass of products x100

Back

Preview of the back of card 5
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