Key Words Flashcards
Aldehyde
An organic compound with the general formula RCHO
Alkaline earth metal
Metals in group 2 of the periodic table
Alkane
The hydrocarbon with C-C and C-H single bond
Allotopes
Pure elements which can exist in different physical forms in which their atoms are arranged differently.
Anaerobic respiration
The process which energy is released and new compounds fromed in living things in the absences of oxygen
Atom economy
Efficiently of a chemical reaction by comparing the total number of atoms in the product with starting total
Atomic orbital
A region space around an atomic nucleus where there is a high probability of finding an electron
Avogadro constant
The total number of particles in a mole of substance.
Bond dissociation enthalpy
The enthalpy change required to break a covalent bond with all species in the gaseous state
Calorimeter
An instrument for measuring the heat change that accompany a chemical reaction
Catalyst
A substance that alters the rate of a chemical reaction but is not used up in the reaction
Catalytic cracking
The breaking, with the aid of a catalyst, of long chain alkane molecules into shorter hydrocarbons
Carbocation
An organic ion in which one of the carbon atoms has a positive charge
Carbon-netraul
A process or series of processes in which as much carbon dioxide is absorbed from the air as is given out
Chemical feedstock
The starting materials in an industrial chemical reaction
Co-ordinate bonding
Covalent bonding in which both electrons in the bond come from one of the atoms in the bond
Covalent bonding
Describes a chemical bond in pair of electrons are shared between two atoms
Activation energy
The minimum energy that a particle in order to react: the energy difference between the reactants and transition state
Dative covalent bond
Covalent bonding in which both electrons in the bond come from one the binds in the pair
Delocalised electron
Describes electron that are spread over several atoms and help to bond them together
Dipole-dipole force
An intermolecular force that results from the attraction between molecules with permeant dipoles
Displacement reaction
A chemical reaction in which one atom or group of atom replaces another in a compound
Displayed formula
The formula of a compound drawn out so that each atom and each bond is shown
Disproportionation
Describes a redox reaction in which the oxidation number of some atoms of a particular element increases and that of other atoms of the same element decreases
Dynamic equilibrium
A situation in which the composition of a contrast concentration reaction mixture does not change because both forward and backward reactions are proceeding at the same rate
Electron density
The probability of electrons being found in a particular volume of space
Electron pair repulsion theory
A theory which explains the shapes of simple molecules by assuming that pairs of electrons around a central atom repel each other and thus take up positions as far away as possible from each other in space
Electronegativity
The power of an atom to attract the electrons in covalent bond
Electrophile
An electron-deficient atom, ion or molecules that takes part in an organic reaction by attacking areas of high electron density in another reactant
Electrophilic addition
A reaction in which a carbon-carbon double bond is attacking an electrophile
Electrostatic forces
The forces of attraction and repulsion between electrically charged particles
Elimination
A reaction in which an atom or group of atoms is removed from a rectant
Empirical formula
The simplest whole number ratio of atoms of each element in a compound
Endothermic
Describes a reaction in which heat is taken in as the reactant change to products
Enthalpy change
A measure of heat energy given out and taken in when a chemical or physical change occurs at constant pressure
Enthalpy diagrams
Diagrams in which the enthalpies of the reactants and products of a chemical reaction are plotted on a vertical scale to show their relative levels
Equilibrium mixture
The mixture of reactants and products formed when a reversible reaction is allowed to proceed in a closed container until no further change occurs. The forward and backwards reaction are still proceeding but at the same rate
Exothermic
Describes a reaction in which heat is given out as the temperature thus rise
Fingerprints region
The area of an infra-red spectrum below about 1500 cm-1. It is caused by complex vibrations of the whole molecule and is characteristic of a particular molecules
Fraction
A mixture a hydrocarbons collected over a particular range of boiling points during the fractionation crude oil
Free radical
A chemical species with an unpaired electron
Functional group
An atom or group of toms in an organic molecule which is responsible for the reaction of that molecule
Group
A vertical column of elements in the periodic table. The elements have similar properties because they have the same outer electron arrangement
Half equation
An equation for the redox reaction which considers just one of the species involved and shows explicitly the electrons transferred to or from it
Homologous series
A set of organic compound with the same functional group. The compounds differ in the length of their hydrocarbon chains
Hydrogen bonding
A type of intermolecular force in which hydrogen atom interacts with a more electronegative atom
Incomplete combustion
A combustion reaction in which there is insufficient oxygen for all the carbon in the fuel to burn to carbon dioxide. Carbon monoxide is formed
Ionic bonding
Describes a chemical bond in which an electron or electrons are transferred from one atom to another, resulting in the formation of oppositely charged ions with electrostatic forces of attraction between them
Ionisation energy
The energy required to remove a mole of electrons from a mole of isolated gaseous atoms or ions
Isomer
One of two compounds with the same molecular formula but different arrangement of atoms in space
Ketone
An organic compounds with the general formula with a c=o
Lattice
A regular three dimensional arrangement of atoms, ions and molecules
Leaving group
In an organic substitution reaction, the leaving group is an atom or group of atoms that is ejected from the starting material, normally taking with it an electron pair and forming a negative ion
Lone pair
A pair of electrons in the outer shell of an atom that is not involved in bonding
Maxwell-Boltzmann distribution
The distribution of energies of the molecules in a gas or liquid
Mean bond enthalpy
The average value of the bond dissociation enthalpy for a given type of bond taken from a range of different compounds
metallic bonding
describes a chemical bond in which outer electrons are delocalised within the lattice of metal ions
mole
a quality o f a substance that contains the Avogadro number of particles
molecular formula
a formula that tells us the actual numbers of atoms of each different element that makes up a molecule of a compound
molecular ion
in mass spectrometry this is a molecule of the sample which has been ionised but which has not broken up during its flight through the instrument
monomer
a small molecule that combines with many other monomers to form a polymer
nucleons
protons and neutrons
nucleophile
an ion or group of atoms with a negatively-charged area that takes part in an organic reaction by attacking an electron-deficient area in another reactant
nucleophilic substitution
an organic reaction in which a molecule with a partially positively charged carbon atom is attacked by a reagent with a negatively charged area.
nucleus
the tiny, positively charged centre of an atom
oxidation
a reaction in which an atom or group of atom lose electrons
oxidation state (oxidation number)
the number of electrons lost or gained by an atom in a compound to the uncombined atom. it forms the basis of a way of keeping track of redox reaction
oxidising agent
a reagent that oxidised another species
percentage yield
in a chemical reaction, this is the actual amount of product produced divided by the theoretical amount
period
a horizontal row of elements in the periodic table.
periodicity
regular recurrence of the properties of elements when they are arranged in atomic number order
polar
describes a molecule in which the charge is not symmetrically distributed so that one area is slightly positively charged and another slightly negatively charged
positive inductive effect
describes the tendency of some atoms or groups of atoms to release electrons via a covalent bond
proton number
the number of protons in the nucleus of an atom
redox reaction
oxidation and redox reaction
reducing agent
a reagent that reduces another species
reduction
a reaction in which an atom or group of atoms gain electrons
relative atomic mass
average mass of an atom / (1/12) of the mass of 1 atom of carbon 12
relative formula mass
average mass of an entity / (1/12) of the mass of 1 atom of carbon 12
relative molecular mass
average mass of an molecule / (1/12) of the mass of 1 atom of carbon 12
saturated hydrocarbon
a compound containing only hydrogen and carbon bonds only
specific heat capacity
the amount of heat needed to raise the temperature of 1g of substance by 1K
spectator ions
ions that are uncharged during a chemical reaction, that is, they take no part in the reaction
standard molar enthalpy change of combustion
the enthalpy change when 1 mole of a substance is completely burned in oxygen with all reactants and products in their standard states
standard molar enthalpy change of formation
the enthalpy change when 1 mole of substance is formed from its elements with all reactants and products in their standard states
stereoisomer
isomer with the same molecular formula and the same structure, but a different position of atoms in space
stoichiometry
describes the simple whole number ratios in which chemical species react
strong nuclear force
the force that holds protons and neutrons together in the nucleus
structural formula
a way of writing the formula of an organic compound in which bonds are not shown but each carbon atom is written separately with the atom or groups of atoms attached to it
structural isomer
isomer with the same molecular formula but a different structure
thermochemical cycle
a sequence of chemcial reactions that convert a reactant into a product. the total enthalpy hcange of the sequence of reactions will be the same as that for the conversion of the recatnats to the product directly
van der Waals force
an intermolecular force of attraction that is caused by instantaneous dipoles and acts between all atoms and molcules
