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CHEM 110
Block 3 Kinetics Definitions
Question | Answer |
---|---|
Oscillating reaction | Product appears as a series of bursts and concentrations of intermediates rise and fall periodically with time |
Explosions occur because | Concentration of intermediates increases rapidly as reaction proceeds. |
Competing/parallel reactions | Lead to different products from the same reactants |
Michalis and Menten Mechanism | A substrate (reactant) and enzyme react reversibly to form a short-lived enzyme-substrate complex; in the slow step this complex then breaks down to form the product plus enzyme again. |
Catalysts | Substance that speeds up a reaction without istelf being consumed in the overall process |
Homogenous Catalyst | Catalyst which works in the same phase as the reaction itself |
Heterogenous Catalyst | Catalyst which operates in a different phase to the reaction |
Rate determining step | slowest step in a reaction mechanism |
Reactive Intermediates | shortlived relative species that appear in one step and react in a later step in the reaction mechanism |
Reaction Mechanism | Sequence of elementary reactions leading to overall reaction |
Transition state | (in elementary reaction) is the point of highest energy between reactants and products |
Elementary reaction | Step where molecules collide. Order of elementary reaction is given by the stoichiometery of the reaction. |
Collision Theory | Assumes molecules react by breaking and making bonds. Reacting molecules must meet of collide with sufficient energy and in correct orientation |
Half-life | Time for the concentration of reactant to fall to 1/2 its initial value. |
Rate law | Relationship between rate and concentration. Proportional in 1st order and proportional to the square in second order. |
Rate | Change in concentration per unit time |