(3) Rate of Reaction Flashcards
equation to find rate of reaction
change of conc/time
what happens when rate is increased
frequency of collisions inc and no. of particles with energy greater than Ea
what factors affect rate
temp and conc
how does temp affect rate
inc temp, inc Ek of particles, inc collisions, inc successful collisions in given time (inc rate)
how does conc affect rate
inc conc, inc no. of particles in a volume, more successful collisions in given time (inc rate)
what is rate determining step
the speed of the slowest step in a reaction
what is the rate equation
rate=k[A]ᵐ[B]ⁿ
what is k in a rate equation
rate constant if temp and Ea is constant
define order of reaction
the power to which conc of a reactant is raised in the rate equation
what is the overall order of a reaction
the sum of the power to which the conc of a reactant is raised
zero order
conc does not affect rate (doesn’t appear in equation)
first order
whatever happens to conc, same happens to rate (directly proportional)
second order
whatever you to do conc, the square of that happens to rate (triple conc, 3² rate)
rate constant unit 1,2,3,4,5
s⁻¹
mol⁻¹dm³s⁻¹
mol⁻²dm⁶s⁻¹
mol⁻³dm⁹s⁻¹
mol⁻⁴dm¹²s⁻¹
what experient would you use a colorimeter
if substance is coloured
what experiment would you use a gas syringe
if product is a gas (volume of gas over time)
what experiment would you use a flask and balance
if product is gas (mass of gas over time)
what experiment would you record pH
if H⁺ or OH⁻ ions are present in reaction
why do you quench a sample in titrations and how would you do so
to stop the reaction, rapid cooling/add large vol. of water/add chemical to remove reactant not being monitored
when are progressive rate methods used
during reaction
zero order conc-time graph
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first order conc-time graph
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second order conc-time graph
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when are inital rate methods used
when reaction starts (t=0)
zero order rate-conc graph
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first order rate-conc graph
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second order rate-conc graph
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what is a nucleophile
a molecule that is attracted to a positive charge
when RDS uses 2 molecules (hydrolysis)
biomolecular nucleophilic substituion (Sᴺ2)
how to know what is involved in RDS
molecules included in the rate equation (not zero order)
when RDS uses 1 molecule (hydrolysis)
unimolecular nucleophilic substitution (Sᴺ1)
