2: Reaction Kinetics Ⅱ Flashcards
What is a clock reaction
In a clock reaction, we find an approximate value for the initial rate of reaction by measuring the time it takes for a certain amount of product to form. In some cases this can be measured quite precisely by observing an abrupt colour change
What is the rate determining step
The slowest step in the reaction pathway
What are the number of moles of a particular reactant in the rate determining step equivalent to
The order reaction for the reactant
How to find the rate equation if the slow step is not the first step in the mechanism
Add together all the steps up to and including the slow step. The number of particles of each substance reacting in this combined equation will be the order of reaction for that substance
How does the temperature effect the Boltzmann distribution
At higher temperatures, there will be a higher area past the activation line
(Remember the total area under the line is still the same)
How does temperature affect rate of reaction and why
Rate of reaction increases with higher temperature as more particles have more energy than the activation energy and particles have more kinetic energy, so collide more frequently
What is the Arrhenius equation
k= Ae^(-Ea/RxT)
It is on the data sheet
What is the pre-exponential factor (A)
This is the term which relates the concentrations of
reactants to the frequency of collisions
What is R in the Arrhenius equation
The Gas constant (8.314)
What is the units of temperature in the Arrhenius equation
Kelvin K
What are the units for activation energy in the Arrhenius equation
Jmol¯¹
How can the natural log of the Arrhenius equation be written to give the equation of a line
ln(k) = (-Ea/R) x (1/T) + ln(A)
y = mx + c
What is the gradient of a ln(k) against 1/T graph equal to
-Ea/R
Ea is activation energy
R is gas constant
What is the y-intercept equal to on a ln(k) against 1/T gragh
ln(A)
Natural log of the pre-exponential factor
