Please enable JavaScript.
Coggle requires JavaScript to display documents.
Energetics 1.4 - Coggle Diagram
Energetics 1.4
Definitions
-
-
Mean enthalpy bond - heat energy required to break one mole a covalent bond averaged for that type of bond in a range of different compounds
Standard enthalpy of formation - enthalpy change that occurs when one mole of compound is formed from its elements with all reactants and products in their standard states
Standard enthalpy of combustion - enthalpy change when one mole of a compound reacts with oxygen completely with all reactants and products in standard state
-
Bond Enthalpies
-
-
-
Limitations; Bond enthalpies are mean values that come from a range of compounds - only apply to reactions in its gaseous state
Hess's Law
Not always possible to measure enthalpy change of a reaction directly - Reactions can be too slow, Ea is too high
-
-
-
-
-
Step 4: Rearrange to find the enthalpy change required (may have to double/triple some aspects depending on number of moles
Exothermic & Endothermic
Exothermic
-
Important reactions; Combustion, Respiration
-
-
Endothermic
-
-
Reactions; Thermal decomposition, photosynthesis
-
-
Standard enthalpies
Formation
-
Temp(298K), Pressure (100kPa)