Endo And Exothermic Reactions Flashcards
Exothermic
Release heat to surroundings
Combustion
Displacement
Neutralisation
Endothermic
Takes heat in from surroundings
Decomposition
Bond energy
Amount of energy needed to break a bond in kj mol
Energy put in to break chemical bonds
Endothermic
Energy released to make chemical bonds
Exothermic
Reversible reactions
Closed system
Reactants collide and turn into products, conc of reactants decreases
Forward and back reaction happen at same rate
No change in amounts of products or reactants
Dynamic equlibrium
Le Chateliers Principle
If a dynamic equilibrium is disturbed by changing conditions, the position of equilibrium shifts to counter this change
Pressure
Increase, move to side with less gas molecules
Decrease, move to side with more gas molecules
Temperature
Increase, endothermic reaction
Decrease, exothermic reaction
Catalysts
No effect on p of e
Rate changes by same amount
Haber process
Nitrogen from air Hydrogen from natural gas 450C 200atm Iron catalyst Gas cooled, liquid ammonia Unreacted gas recycled
Temp of 450C
Compromise, rate too slow
Iron catalyst
Increase rate of reaction
Does not change yield, max ammonia in shortest amount of time
Uses of ammonia
Fertiliser
Nitric acid
Contact process
Burn sulphur in oxygen, heat sulphide ores strongly
React sulphur dioxide with oxygen
Add sulphuric acid to sulphur trioxide to get oleum
Oleum and water gets sulphuric acid
450C
1-2atm
Vanadium catalyst
