IB syllabus > energetics ((sl) > 6.1 

These notes were written for the old IB syllabus (2009). The new IB syllabus for first examinations 2016 can be accessed by clicking the link below.

IB syllabus for first examinations 2016

6.1 - Exo and endothermic reactions


6.1.1: Define the terms exothermic reaction, endothermic reaction and standard enthalpy change of reaction (? HØ). Standard enthalpy change is the heat transferred under standard conditions - pressure 101,3kPa, temperature 298K. Only ? H can be measured, not H for the initial or final state of a system


 

 

 


6.1.2: State the relationship between temperature change, enthalpy change and whether a reaction is endothermic or exothermic. Combustion of organic compounds are good examples of exothermic reactions


 

 

 

 


6.1.3: Deduce from an enthalpy level diagam the relative stabilities of reactants and products and the sign of the enthalpy change for the reaction. If the final state is more stable (lower on the enthalpy level diagram) this implies that H final < H initial and ? H must be negative. Energy must be released in going to a more stable state.


 

 

 

 


6.1.4: Describe and explain the changes which take place on a molecular level in chemical reactions. Relate bond formation to the release of energy and bond breaking to the absorption of energy


 


6.1.5: Suggest suitable experimental procedures for measuring enthalpy changes of reactions in aqueous solution Explore different reactions operating at constant pressure (open containers). Use of the bomb calorimeter is not required.






 


Resources




Useful links