u1: rates of reaction Flashcards
chemical kinetics
area of chemistry that deals w/ rates of change (wht makes reactions go slow/fast)
kinetics
how fast a reaction proceeds
rate of a chemical reaction
how fast the concentration of a reactant or product in a chemical reaction changes
reaction rates formula
r = change in concentration / change in time
what does the sign of the reaction rate tell you
- pos: formation of product
- neg: consumption of reactant
average rate of reaction
- speed at which reaction occurs over a period of time
- concentration of reactant/product over time
instantaneous rate of reaction
- rate of a reaction at a particular point in time
- slope of tangent line
when reporting reaction rate, you must _____
specify which reactant or product was monitered since they dont always occur in a 1:1 ratio
average rate of reaction typically ________
why?
- decreases over time
- bc concentration of reactants decreases over time nd reaction rate usually dependent on reactant concentration
which properties could be used to measure reaction rates
- any property that changes between start and end theoretically
- want properties w/ large changes
- property should be directly proportional to concentration (so pH not rec bc logarithmic)
reactions that produce a gas
- collect gas produced and quantify volume nd pressure
- greater change in volume nd pressure means faster the reaction
- use PV = nRT to determine change in mols over time
measurement of mass in reactions that produce a gas
- total mass will be lost if gas is produced
- for effectiveness, gas produced should have high molar mass so theres a significant changes in mass
- use n=m/M to find changes in mols over time
reactions that involve ions
- measure change in conductivity and plot as function of time
- faster the reaction = more ions produced = better conductivity
reactions that change colour
- measure the intensity of a colored reactant or product using a spectrophotometer
