Reactions Rates

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  • Created by: Voltace
  • Created on: 26-05-14 15:56
What is collision theory?
Reactions won't take place between two particles unless they collide in the right direction with the minimum amount of kinetic energy (called activation energy)
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What are enthalpy profile diagrams?
Used to work out enthalpy change ⌂H, Difference between reactants & Products = Enthalpy change, if products are lower enthalpy = Exothermic if products higher = Endothermic
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What are Maxwell-Boltzmann Distributions? & how are they affected by tempreature, concentration & pressure
a graph showing no. of molecules in a gas with different kinetic energies. Small no. with activation energy. Temp =Increase in temp, more kine engy, pushes to right area still same. Concentration: particles closer, collide more, more with activation
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What are catalysts? & how do they affect reactions?
A catalyst increases rate of reaction by providing alternative reaction pathway, with a lower A.E and chemically unchanged. Save money, lowers activation , same amnt of engy, but engy needed lowered, just increases rate. only works on single reaction
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What do you need for Dynamic Equillibrium?
Dynamic Equilibrium - Only in closed system & reversible reaction
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What is the definition of Le Chatleirs Principle?
Change in concentration, pressure , tempreature equilbirium will move to counter-act the change.
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Explain how change in concentration , pressure & tempreature affect position of equillibrium
Conc = Increase reactants = more product formed (shifts right) Tempreature = Increase shifts to endothermic side, Decrease in temp shifts to exothermic side for more heat Pressure = gasses, increase shift to side with fewer molecules & vice versa
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Explain about Ethanol production
(Reversible. Phosphoric acid catalyst, steam+ethene (c2h4+h20->c2h5OH) Exothermic-> lower temp more yield, slower reaction, compromise between each. Pressure favours forward - high pressure (Expensive) Unreacted ethene re-cycled.
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Explain about Methanol production
(Reversible. 2h2 +CO -> CH30H) Exothermic -> favours lower tempreature, High pressure favoured (expensive) catalyst =mix of copper, zinc and aluminium oxide
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What are the importances of Ethanol & Methanol
Ethanol: Fuel , both used for fuels (can be added to petrol or own) , Carbon neutral Methanol: Solvent, used to make other chemicals, Fuel , both used for fuels (can be added to petrol or own) , Carbon neutral
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Other cards in this set

Card 2

Front

What are enthalpy profile diagrams?

Back

Used to work out enthalpy change ⌂H, Difference between reactants & Products = Enthalpy change, if products are lower enthalpy = Exothermic if products higher = Endothermic

Card 3

Front

What are Maxwell-Boltzmann Distributions? & how are they affected by tempreature, concentration & pressure

Back

Preview of the front of card 3

Card 4

Front

What are catalysts? & how do they affect reactions?

Back

Preview of the front of card 4

Card 5

Front

What do you need for Dynamic Equillibrium?

Back

Preview of the front of card 5
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