5.7 reaction kinetics 🏃♀️ Flashcards
define activation energy
activation energy is the minimum amount of energy, which reactant particles must possess to overcome the energy barrier in order for effective collisions to result in a chemical reaction
factors affecting rate of reaction
1) temperature
2) catalyst
3) concentration of reactants
4) physical state of reactant
5) light
how does temperature increase rate of reaction?
- at higher temp, total number of particles remain unchanged but the average kinetic energy of reactant particles increases
- number of reactant particles with energy greater than or equal to activation energy increases
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how does the concentration of reactant increase rate of reaction?
- when conc increases, number of reactant particles per unit volume increases
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how does the physical state of reactants increase rate of reaction?
- for more finely divided, the surface area over which the solid can come into contact with liquid gaseous increases
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how does catalyst increase rate of reaction?
- catalyst provides an alternate pathway with lower activation energy
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define order of reaction
rate of reaction is the power to which the concentration of reactant is raised to in the rate equation
define half-life of a reaction
half-life of a reaction is the time taken for the concentration of the reactant, A to decrease to half its original value (ln2 / k)
define the elementary step in a reaction mechanism
the elementary step is the simplest step which cannot be broken down into smaller step
what are homogenous catalysts?
catalyst that acts in the same phase as reactants, providing an alternate pathway for reactants by forming reaction intermediates
what are heterogenous catalysts?
catalyst that acts in a different phase as reactants, lowering activation energy by means of adsorption
define adsorption
adsorption is the adhesion of substance to the surface of another substance
