Definitions from Past Papers (Chemistry)

All the definition questions from the OCR Unit 2 AS Chemistry from June 2009 to June 2012 listed under seperate years. Answers are taken from the mark scheme.

HideShow resource information
Preview of Definitions from Past Papers (Chemistry)

First 313 words of the document:

Sarah Stancombe- Chains, Energy and Resources (F322)
June 2009
Enthalpy Change of Combustion- The enthalpy change for the complete combustion of 1 mol (of a substance).
Standard Conditions- pressure: 100 kPa and temperature: 298 K.
Atom Economy- (sum of) the molecular masses of the desired product ÷ sum of molecular masses of all
products × 100.
January 2010
Radical- Species with an unpaired electron.
Le Chatelier's Principle- The position of equilibrium will shift so as to minimise the effect of any change in
Structural Isomer- Same molecular formula but different structural formulae.
June 2010
Homologous Series- Series having same functional group and a general formula.
Standard Enthalpy Change of Formation- (Enthalpy change) when one mole of a compound is made from its
elements (in their standard states). (Standard conditions are) 298 K and 100 kPa.
January 2011
Enthalpy Change of Reaction- (enthalpy change when) the number of moles of reactants as specified in the
(balanced) equation react together.
Average Bond Enthalpy- (Enthalpy change) when one mole of bonds of (gaseous covalent) bonds is broken.
June 2011
Enthalpy Change of Combustion- (Enthalpy change) when one mole of a substance is completely combusted.
Functional Group- group of atoms that give a compound its (characteristic set of) reactions.
Endothermic- Reaction in which energy enters the system (from the surroundings).
Activation Energy- Activation energy is the minimum amount of energy needed for the reactants to react.
January 2012
Stereoisomerism- Same structural formula but a different arrangement of groups around a double bond.
Functional Group- Group of atoms (in a molecule or compound) that is responsible for the reactions.
Radical- species with an unpaired electron.
Standard Enthalpy Change of Formation- (Enthalpy change) when one mole of a compound is formed from its
elements at298 K and 100 kPa.



Well, this just made my life 10x easier. Thanks! :)

Similar Chemistry resources:

See all Chemistry resources »See all resources »