AQA AS Organic Chemistry exam questions with 100% correct answers

Define the term 'empirical formula' - ANSWERS A formula that gives the simplist whole number ration of atoms of each element in a compound Define the term 'molecular formula' - ANSWERS A way of representing molecules that shows the actual number of atoms of each element in a molecule Define the term 'General formula' - ANSWERS An algebraic formula that can describe any member of a family of compounds Define the term 'Structural formula' - ANSWERS A way of representing molecules that shows the atoms carbon by carbon, with the attached hydrogens and functional groups Define the term 'Displayed formula' - ANSWERS A way of representing a molecule that shows every atom and every bond Define the term 'Skeletal formula' - ANSWERS A simplified organic formula which only shows the carbon skeleton and associated functional groups How do you draw structures in 3D? - ANSWERS Wedges - Bonds coming out of the paper Dotted lines - Bonds going into the paper Normal lines - Bonds in the plane of the paper Define the term 'Homologous series' - ANSWERS A family of organic compounds that have the same general formula and similar chemical properties Define the term 'Structural isomer' - ANSWERS A molecule with the same molecular formula as, but different structural formula to another molecule Define the term 'Stereoisomerism' - ANSWERS A molecule which has the same structural formula as another molecule, but has its atoms arranged differently in space Define the term 'E-isomer' - ANSWERS A stereoisomer of an alkene that had the two highest priority groups on opposite sides of the carbon-carbon double bond Define the term 'Z-isomer' - ANSWERS A stereoisomer of an alkene that has the two highest priority groups on the same side of the carbon-carbon double bond (To help you remember it: Zee Zame Zide). Define the term 'E/Z isomerism' - ANSWERS A type of stereoisomerism that is cause ld by the restricted rotation about a carbon-carbon double bond, each of he carbon atoms must have two different groups attached Define the term 'Alkanes' - ANSWERS A saturated hydrocarbon with the general formula CnH2n+2 Define the term 'Petroleum' - ANSWERS A mixture consisting mainly of alkane hydrocarbons that can be separated into different fractions Define the term 'Cracking' - ANSWERS Long chain hydrocarbons are broken down into shorter chain hydrocarbons. This produces a mixture of alkanes and alkenes Describe thermal cracking. Include conditions in your answer. - ANSWERS Temperatures between 700k and 1200k Pressure of up to 7000 KPa. 1) Carbon-carbon breaks to produce two free radicals