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23 Cards in this Set
- Front
- Back
chemical kinetics
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study of reaction rates.
can give insights into whats happening at the molecular level in a reaction |
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reaction rate
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increase in molar concentration of a product of a reaction per unit time
OR decrease in molar concentration of a reactant per unit time |
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initial rate
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fastest rate in a reaction
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reaction rate proportions
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reactants
# of effective molar collisions 1 / activation energy catalyst reaction temperature surface area of solid reactant or catalyst |
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activated complex(transition state)
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an unstable grouping of atoms that can break up to form products.
symbol: double dagger |
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activation energy
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minimum energy of collision required for 2 molecules to react
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progress of reaction
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has nothing to do with time
lower energy tends to be more stable |
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rate constant
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a proportionality constant that relates rate and reactant concentrations
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rate law
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indicates how the rate of reaction changes as reactants change
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half life
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time required for the reactant to decrease to one-half of its initial value
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reaction mechanism
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the pathway the reaction takes
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elementary reactions
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individual steps in the larger overall reaction
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unimolecular
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rxn only involves one reactant molecule (falls apart)
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bimolecular
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rxn involves the collision of 2 reactant molecules
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termolecular
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rxn requires the collision of 3 reactant molecules.
all 3 things happen at the same time |
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dynamic equilibrium
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consists of forward rx, in which reactants react to give products, amd a reverse rxn, in which products react to give original reactants
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chemical equilibrium
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(dynamic equilibrium) is the state reached by a rxn mixture when the forward rates = reverse rates
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law of mass action
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dictates that a rxn will always settle into an equilibrium where the equilibrium-constant expression equals K (for particular rxn at given T and P), regardless of the initial concentration of the reactants and/or products that are mixed together
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K(overall)
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= K (a《》x) × K (x 《》b)
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heterogeneous equilibrium
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reactants and products in more than one phase
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le chatelier's principle
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when a system in a chemical equilibrium is disturbed by a change of concentration (reactant or product), volume (pressure), or temperature, the equilibrium will shift in a way that tends to counteract this change.
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effect of temp change
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endothermic adds heat to reactant
exothermic adds heat to product |
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catalyst
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a substance that increases the rate of a rxn but is not consumed by it
has no effect on equilibrium composition, wont make something happen that wouldnt in the first place |