buffers, redox and oxidation

• organic chemistry is the study of carbon compounds
• hydrocarbons are compounds made of hydrogen and carbon
• alkanes are hydrocarbons with only single bonds between carbon atoms.
• alkenes are hydrocarbons with at least one double bond between carbon atoms
• alkanes are saturated because each carbon is bonded to the maximum number of atoms
• alkanes have a general formula of CnH2n+n
• 1 C atom in a chain is meth-
• 2 C atoms in a chain is eth-
• 3 C atoms in a chain is prop-
• 4 C atoms in a chain is but-
• 5 C atoms in a chain is pent-
• 6 C atoms in a chain is hex-
• 7 C atoms in a chain is hept-
• 8 C atoms in a chain is oct-
• 9 C atoms in a chain is non-
• 10 C atoms in a chain dec-
• isomers are compounds with the same molecular formula, but different structures/arrangement of atoms. isomers may have different physical and chemical properties
• chain structural isomers differ in the length of their longest chain.
• position structural isomers differ in the point of attachment of a methyl group.
• combustion is the reaction of an alkane or alkene with oxygen, to produce carbon dioxide and water.
• limited combustion occurs when hydrocarbons react with limited oxygen, producing carbon monoxide, soot and carbon dioxide.
• substitution only occurs when uv light is present and is the process of replacing hydrogen atoms with halogens.
• the products of substitution in alkanes are called haloalkanes
• cyclic alkanes are formed when carbon atoms are connected in a ring structure and are isomers with alkenes. every bend represents a carbon atom.
• alkenes are carbon compounds that contain double or triple bonds between carbon atoms that are unsaturated.
• the stem of alkenes is numbered from the end that places the double bond at the smallest number possible.
• geometric isomers can only exist in alkenes, and have the same molecular formula but the groups attached to carbon atoms, joined by a double bond, are in different positions in space
• a geometric isomer with the two groups on the same side of the carbon atoms are called 'cis' isomers
• a geometric isomer with the two groups on opposite sides of the carbon atoms are called 'trans' isomers
• addition reactions occur in alkenes, and are reactions in which the double bond between carbon atoms is broken, and becomes a single bond, adding two atoms where the double bond used to be.
• alkanes and alkenes can be distinguished by adding a solution of bromide
• Alkanes are hydrocarbons with only single bonds between carbon atoms, while alkenes are hydrocarbons with at least one double bond between carbon atoms.
• benzene is the simplest member of a class of hydrocarbons called aromatics, which are cyclical and unsaturated.
• benzene is made up of six carbon atoms joined in a ring, with one hydrogen atom singly bonded to each carbon.
• the bonds in benzene are neither double nor single.
• chemically, benzenes behave more like an alkane than an alkene as it does not contain any double bonds, so undergoes combustion and substitution reactions.
• substitution reactions of benzene require a catalyst and high temperature
• a buffer is a solution whose pH remains almost constant (resists changes in pH), when small quantities of a strong acid or base are added to it.

  the pH change of the solution is minimised.
• buffer solutions are made from either a mixture of a weak acid and its conjugate base or a mix of a weak base and its conjugate acid.
• in a buffer solution, the weak acid acts as a source of protons to neutralise the added base and the weak base absorbs added protons.