Chemistry II - Exam 1 Study Set

kinetics

the study of the factors that affect the speed of a reaction and the mechanism by which a reaction proceeds

rate

how much a quantity changes in a given period of time; slows down over time

average rate

the change in measured concentrations in any particular time period

instantaneous rate

the rate at which something is occurring at any specific time; is more accurate than average rate

nature of reactants

size of molecules, states of matter, surface area, reactivity, charge (ion or not), number of bonds; something that affects the rate of a reaction

temperature

something that affects the rate of a reaction; increase in this = increase in reaction rate

catalysts

substances which affect the speed of a reaction without being consumed

concentration

something that “fuels” a reaction and can affect the rate of a reaction; larger “fuel” = faster reaction

1) nature of reactants

2) temperature

3) catalysts

4) concentration

4 factors that affect reaction rates

rate laws

mathematical expressions that describe the relationship between the rate of a chemical reaction and the concentration of its reactants

reaction order/order of the reaction

the sum of the exponents of the reactants

integrated rate laws

a rate law that relates the concentrations of reactants and time

half-life of a reaction

the time required for the concentration of a reactant to be one half its initial value; only is applicable to first order reactions

frequency factor/collision frequency

the number of molecules that approach the energy barrier in a given period of time

energy of activation

energy barrier that must be passed for a chemical reaction to proceed

effective collision

collisions with sufficient energy and proper orientation

activated complex/transition state

when molecules have an effective collision, a temporary, high energy, unstable chemical species is formed