A1.1 Water

acid

a substance that can donate one or more protons and so become negatively charged, for example deoxyribonucleic acid (DNA)

atom

a unit of matter with positively charged protons grouped in the nucleus and negatively charged electrons in orbitals around the nucleus; atoms have no net charge because the number of protons and electrons equal

base

a substance that can accept one or more protons and so become positively charged, for example adenine and other bases in DNA

catalyst

a substance that increases the rate of reaction but is itself unchanged at the end of the reaction

concentration

the amount of substance per unit volume

condensation

a reaction in which two molecules are combined into one molecule and water is eliminated

covalent bond

a region of high electron density between two atoms due to the sharing of a pair of electrons, which attracts the nuclei of both atoms, holding them together

hydrogen bond

an attraction between an electronegative atom (such as oxygen) and a hydrogen atom bonded to another electronegative atom

hydrolysis

the separation of one molecule into two using hydrogen (H_ and hydroxyl groups (OH) released by splitting a water molecule

hydrophilic

having an affinity (attraction) for water

hydrophobic

have a low affinity for water and more affinity for non-polar molecules

intermolecular force

an attraction between molecules; a bond between atoms within a molecule

ion

an atom or molecule that has become positively charged by losing one or more electrons or negatively charged by gaining one or more electrons

ionic bond

a bond formed by attraction between positively-charged and negatively-charged ions or groups on molecules

isotope

one of the two or more alternative forms of an element, with the same number of protons and electrons per atom as other forms, but a different number of neutrons.

macromolecule

a molecule with a molecular mass of more than 10,000

molecule

two ormore atoms joined together by one or more covalent bonds

oxidation

a reaction in which hydrogen is removed, electrons are removed, or oxygen is added

pigment

a substance that absorbs wavelengths of visible light and so appears colored

polymer

a molecule consisting of a series of many subunits linked by covalent bonds; an oligomer has fewer than 10 subunits

radioactive

a type of isotope with an unstable nucleus with can emit radiation

reduction

a reaction in which a hydrogen is added, electrons are added, or oxygen is removed

solute

a dissolved substance in a solution

solvent

a liquid that can dissolve other substances to make a solution

sythesis

the production of more complex molecules from simpler substances by one or more chemical reactions