CHEM 2080: Prelim 2-A
45 Cards in this Set
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elementary reactions occur in…
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a single step
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reaction mechanisms are a series of…
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elementary reactions
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Intermediate species do not…
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appear in the overall reaction equation
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Intermediate species are produced…
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in one step and consumed in the next
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Define bimolecular reactions
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reactions of two molecules
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Define unimolecular reactions…
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reactions involving a single species
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Collision theory of reaction rates
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two species must collide in order to react
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In reference to collision theory, the rate of reaction = …
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(collision frequency)( fraction of collisions with required energy)(fraction of collisions with the correct orientation)
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collision frequency is proportional to…
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[A][B]
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Activation energy is denoted…
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Ea
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Units of activation energy
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J/mol
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The activation energy is the minimum energy necessary to…
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cause a reaction between colliding molecules
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An activated complex is denoted
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++
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In an activation energy diagram, when the graph is at the maximum, the molecule is…
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unstable
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The rate-determining step states that the rate of the overall reaction cannot be…
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faster than the rate of the slowest step
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Catalysts increase…
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the rate of reaction by providing a faster mechanism
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Catalysts are not…
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consumed in the reaction
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Define termoleculer reaction
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reaction of 3 molecules
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Define homogenous caatalyst
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in the same phase as the reaction mixture
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Define heterogenous catalyst
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in a different phase than the reaction mixture
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Define the Michaelis Menten Mechanism
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Two-step process that involves the formation of an intermediate complex between the enzyme and substrate
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Half-life is the time for a reaction to…
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consume 50% of the reactants
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Half-life is usually dependent on…
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concentration
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Half-life is not dependent on concentration when…
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1st order reactions are involved
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When graphing the rate law, what should be graphed vs. time?
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[A] or log[A] or 1/[A]
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After graphing the rate law, find…
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the most linear plot
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For the rate of elementary reactions, the rate law can be determined from…
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the reaction
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In literal terms, the rate of elementary reactions = …
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(rate of reactants colliding)(Probability of enough energy)(Probability of correct orientation)
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Rate of the reactants colliding depends on…
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concentration
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Probability of enough energy to react dictances dependence on…
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heat
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The forward rate of a reaction relates to…
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the amount of reactant
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Concentration is subject to…
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stoichiometric coefficients
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Concentrations of pure solids and liquids = …
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1.0
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Equilibrium constants should be determined at a specific…
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temperature
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Equilibrium constants are raised to the _____power
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stoichiometric coefficient
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A large Kc yields a large amount of…
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product at equilibrium
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A small Kc yields a small amount of…
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product at equilibrium
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Kp = Kc when…
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the sum of the stoichiometric coefficients of the gaseous reactants = gaseous products
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In terms of Kc, Kp = …
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Kc(RT)^(vgas)
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In terms of Kf, Kr = …
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1/Kf
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Define Le Chatliers Principle
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If a chemical reaction at equilibrium is subjected to a change in conditions displacing it from equilibrium, the reaction adjusts towards a new equilibrium state
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Changes that may affect equilibrium
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concentrations, volume, pressure or temperature
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Value of the equilibrium constant only depends on…
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temperature
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In general, a decrease in volume shifts a reaction in equilibrium toward the side with…
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the smaller number of moles of gas
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In general, an increase in pressure shifts a reaction at equilibrium toward the side with…
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the smaller number of moles of gas
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CHEM 2080: Prelim 1