Chemistry Key Terms

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  • Created by: Kelly
  • Created on: 11-03-14 10:49
Delocalised Electrons
Electrons shared between more than two atoms
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Addition Reaction
Reactant is added to an unsaturated molecule to make a saturated molecule
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Substitution Reaction
an atom or group of atoms is replaced by another atom or group of atoms
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Electrophile
An atom or group of atoms that is attracted to an electron rich centre where it accepts a pair of electrons to form a new covalent bond
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Reaction Mechanism
Is a series of steps that make up an overall reaction
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Curly arrow
Shows the movement of an electron pair in the breaking or formation of covalent bonds
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Functional Group
Part of an organic molecule responsible for it's chemical reactions
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Electronegativity
Measure of the attraction of a bonded atom for the pair of electrons in a covalent bond
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Redox Reaction
A reaction where reduction and oxidation take place
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Reflux
Continual boiling and condensing of a reaction mixture
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Nucleophile
An atom or group of atoms attracted to an electron deficient centre where it donates a pair of electrons to form a new covalent bond
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Hydrolysis
Reaction where water or hydroxide ions breaks down a compound into two compounds
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LDL
Carries cholesterol and triglycerides from the liver to the tissues
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HDL
Removes cholesterol from the blood and back to the liver
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Peptide
Compound made of amino acids linked by peptide bonds
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Zwitterion
Dipolar ionic form of an amino acid formed by the donation of a proton from the carboxyl to the amino group, there is no overall charge
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Isoelectric Point
The pH value where an amino acid exists as a zwitterion
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Condensation Reaction
Two small molecules react together to form a larger molecule with the elimination of water
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Stereoisomers
Species with the same structural formula but with a different arrangement of atoms in space
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Chiral Carbon
Carbon with 4 different atoms or group of atoms attached
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Optical Isomers
Stereoisomers that are non super imposable mirror images of eachother
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Repeat Unit
The specific arrangement of atoms that occurs in the structure over and over again
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Biodegradable Polymer
Breaks down completely into carbon dioxide and water
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Degradable Polymer
Breaks down into smaller fragments when exposed to light, heat or moisture
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Pharmacological Activity
The beneficial or adverse effects of a drug on living matter
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Mobile Phase
The phase that moves in chromatography
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Stationary Phase
The phase that does not move in chromatography
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Adsorption
The process by which a solid holds molecules of gas or liquid or solute as a thin film on the surface of a solid ore more rarely a liquid
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Chromatogram
Visible record showing the result of separation of the components in a mixture by chromatogpraphy
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Rf
Component/Solvent front
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Retention Time
the time taken for a component to pass from the column inlet to the detector
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Chemical Shift
A scale that compares the frequency of and NMR absorption with TMS
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Rate of Reaction
Change in concentration of a reactant or product per unit time
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Initial Rate of Reaction
Change in concentration of a reactant or product per unit time at the start of a reaction where t=0
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Order
With respect to a reactant is the power to which the concentration of the reactant is raised to in the rate equationi
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Rate Constant (k)
The constant that links the rate of reaction with the concentrations of the reactants raised to the powers of their orders in the rate equation
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Half life
The time taken for the concentration of the reactant to reduce by half
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Rate determining step
The slowest step in the reaction mechanism of a multi-step reaction
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Intermediate
Species formed in one step that is used up in another step and is not seen as a reactant or product in the overall equation
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Dynamic Equilibrium
Exists in a closed system when the rate of the forward reaction is equal to the rate of the backward reaction
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Homogeneous Equilibrium
Where all the species making up the reactants and products are the same state
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Heterogeneous Equlibrium
Where the species making up the reactants and products are in different states
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Bronsted Lowry Acid
Proton Donor
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Bronsted Lowry Base
Proton acceptor
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Alkali
Base that dissolves in water froming OH- ions
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Neutralisation
Chemical reaction where and acid and a base react to give a salt + water
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Acid-base Pair
A pair of two species that transform into each other by gain or loss of a proton
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pH
=-log[H+]
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[H+]
=10 to the negative power of pH
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Strong Acid
Completely dissociates in solution
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Weak Acid
Partially dissociates in solution
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pKa
=-log(Ka)
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Ka
=10 the the power of the minus pKa
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Kw
=[H+][OH-] at 25 degrees, Kw is 1.00x10 to the power of minus 14 mol(2)dm(-6)
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Buffer Solution
A mixture that minimises pH changes on addition of a small amount of acid or base
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The Equivalence Point
The point in a titration at which the volume of one solution has reacted exactly with the volume of the second solution (it matches the stoichiometry of the reaction)
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End Point
The point in a titration where there are equal concentrations of the weak acid and conjugate base forms of the indicator. The colour is midway of the colours of the acid and conjugate base
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Standard Enthalpy Change of Neutralisation
The energy change that accompanies the neutralisation of an aq acid by an aq base to form one mole of water under standard conditions
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Lattice Enthalpy
Enthalpy change that accompanies the formation of one mole of an ionic compound from its gaseous ions under standard conditions
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Hess's Law
If a reaction can take place by more than one route and the initial and final conditions are the same, the total enthalpy change for each route is the same
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Standard Enthalpy Change of Formation
Enthalpy change that takes place when one mole of a compound is formed from its constituent elements in their standard states under standard conditions
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Enthalpy Change of Atomisation
Enthalpy change that takes place when one mole of gaseous atoms forms from the element in its standard state
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First Ionisation Energy
Enthalpy change accompanying the removal of one electron from each atom in one mole of gaseous atoms to form one mole of gaseous 1+ ions
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Second Ionisation Energy
Enthalpy change accompanying the removal of one electron from each ion in one mole of gaseous 1+ ions to form one mole of gaseous 2+ ions
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First Electron Affinity
Enthalpy change accompanying the addition of one electron to each atom in one mole of gaseous atoms to from one mole of gaseous 1- ions
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Second Electron Affinity
Enthalpy change accompanying the addition of one electron to each ion in one mole of gaseous 1- ions to form one mole of gaseous 2- ions
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Standard Enthalpy Change of Solution
Enthalpy change that takes place when one mole of a compound is completely dissolved in water under standard conditions
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Standard Enthalpy Change of Hydration
Enthalpy change that takes place when one mole of isolated gaseous ions is dissolved in water forming one mole of aq ions under standard conditions
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Entropy S
The quantitative measure of the degree of disorder in a system
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Standard Entropy Change of Reaction
The entropy change that accompanies a reaction in the molar quantities expressed in a chemical equation under standard conditions, all reactant and products being in their standard states
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Free Energy Change
The balance between enthalpy,entropy and temperature for a process:
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Oxidation/Reduction
Loss of electrons or gain in oxidation number/Gain of electrons or loss in oxidation number
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Standard Electrode Potential of Half Cell
The e.m.f of a half cell compared with a standard hydrogen half cell, measure at 298K with solution concentrations of 1moldm(-3) and a gas pressure of 1 atm
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Transition Element
D-block element that forms an ion with an incomplete d-sub shell
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D-block element
Electrons are filling d-orbitals, the highest energy sub-shell is a d sub-shell
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Complex Ion
Transition metal ion bonded to one or more ligands by coordinate bonds
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Ligand
Molecule or ion that can donate a pair of electrons with the transition metal ion to form a coordinate bond
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Coordination number
The total number of coordinate bonds formed between the central metal ion and its ligands
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Stereoisomers
Species with the same structural formula but with a different arrangement of atoms in space/molecule or complexes with the same SF but different spatial arrangement of these atoms
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Ligand Substitution
A reaction in which one ligand in a complex ion is replaced by another ligand
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Kstab - Stability Constant
The equilibrium constant for an equilibrium existing between a transition metal ion surrounded by water ligands and the complex formed when the same ion has undergone ligand substituiton
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Other cards in this set

Card 2

Front

Reactant is added to an unsaturated molecule to make a saturated molecule

Back

Addition Reaction

Card 3

Front

an atom or group of atoms is replaced by another atom or group of atoms

Back

Preview of the back of card 3

Card 4

Front

An atom or group of atoms that is attracted to an electron rich centre where it accepts a pair of electrons to form a new covalent bond

Back

Preview of the back of card 4

Card 5

Front

Is a series of steps that make up an overall reaction

Back

Preview of the back of card 5
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