Unit 1 A1 chemistry covalent + chromotography

Adsorption

adhering of a component onto the stationary phase

Aqueous solution

solution in which the solvent is water

Chromatogram

visual output of chromatography

Desorption

 release of a component from the stationary phase by dissolving

Dissolved

incorporated into a liquid to form a solution

Eluent

 solvent fluid that moves through a chromatography system

Homogeneous

a mixture with uniform composition and properties

HPLC

 chromatography technique in which the mobile phase is pumped through a tightly packed stationary phase under pressure

Hydrated

surrounded by water molecules

Ion-dipole attraction

electrostatic attraction between a permanent dipole and an ion

Ionisation

process by which a chemical species gains or loses an electron to gain an electric charge

Mobile phase

fluid in a chromatography system that carries the sample over the stationary phase

Origin

line at which samples are placed in paper and thin-layer chromatography

Paper Chromatography

chromatography technique using absorbent paper

Peak area

the area enclosed between the peak and the baseline on a chromatogram

Retention factor

 the ratio of the distance moved by a component to the distance moved by the solvent front

Retention time

 time taken for a component to pass through a HPLC column

Solute

substance that dissolves in a solvent

solution

homogeneous mixture in which a substance is dissolved in another

Solvent

substance that dissolves another substance

Solvent front

the wet moving edge of the solvent in chromatography

Stationary phase

 solid onto which the components of a sample adsorb

Thin-layer chromatography (TLC)

 chromatography technique using a thin stationary phase supported by an inert backing

Bond pair

pair of valence electrons that is shared between atoms in a covalent bond

Covalent bonding

bonding resulting from the sharing of electrons between non-metal atoms

Diatomic molecule

covalently bonded pair of atoms of the same or a different non-metal element

electrostatic attraction

attraction between opposite charges

Intramolecuar bonds

 bonding between atoms within a molecule

Lone pair

electron pairs of valence electrons not shared with another atom in a covalent bond

Molecule

 when two or more non-metal atoms are covalently bonded together

Molecular formula

 actual number of atoms in a molecule

non-polar covalent bond

covalent bond between two atoms of similar electronegativity

Permanent dipole

permanent area of partial positive or partial negative charge on a molecule

Polar covalent bond

covalent bond between atoms of differing electronegativities

Polar molecule

 asymmetrical molecule with a partially positively charged end and a partially negatively charged end

Polarity

property of having a partial positive and negative charge

Structural formula

shows all the atoms and bonds in a molecule or compound

Unpaired electron

electron in an orbital by itself

Valence shell electron pair repulsion theory (VSEPR) 

 model used to predict the different shapes of molecules based on the repulsion between electron pairs