REACTION KINETICS Flashcards
catalyst
substance that speeds up chemical reactions by lowering activation energy by providing alternative pathway without being used up in the process
activation energy Ea
the minimum amount of energy molecules must have in order for the reaction to take place
rate of reaction
the change in concentration of substance( reactant or product) with time
homogenous catalyst
a catalysis in which a reactant and a catalyst are the same phase/state
heterogenous catalyst
a catalysis in which a reactant and a catalyst are the different phase/state
Effect of Concentration Changes
Increasing conc. of reactants increases rate of reaction: more particles per unit volume, collision rate between reacting particles increases,
∴rate of successful collision increases, resulting in increased rate of reaction.
Effect of Pressure Changes
Increasing the pressure of the system increases the rate of reaction: more particles per unit volume, collision rate between reacting particles increases, and rate of successful collision increases, resulting in an increased rate of reaction.
Maxwell-Boltzmann Theory
Explains effect of temp. & catalyst on rate of reaction
Based on distribution of energy among reacting molecules under different conditions
Effect of Temperature
Number of collisions and chance of success will increase
Effect of Catalyst
It does not alter the chemical composition of substances and only lowers the activation energy
It provides a new route or mechanism to follow for reactants that requires less energy
Curve unchanged; only activation energy changes
Enzymes
a protein molecule that is a biological catalyst. Most are specific to a substrate & function as lock-key
