Flashcards in 18.5 - Rate constants and temperature Deck (15):
What is the effect on the rate constant if the temperature increases?
The rate constant also increases
Why does increasing temperature increase the rate constant?
Boltzmann distribution shifts right, increasing the proportion of particles that exceed the activation energy
Particles move faster and therefore collide more frequently (higher chance of correct orientation)
What is the Arrhenius equation?
k = A e -Ea/RT
What is k in the Arrhenius equation?
What is A in the Arrhenius equation?
What is e -Ea/RT in the Arrhenius equation?
What is Ea?
What is R in the Arrhenius equation?
Gas constant = 8.314 J mol-1 K-1
What are the units for R?
J mol-1 K-1
What are the units for T in the Arrhenius equation?
What does the exponential factor represent?
The proportion of molecules that exceed Ea and have sufficient energy for a reaction to take place
What does the pre-exponential factor represent?
The frequency of collisions with the correct orientation
What is the logarithmic form of the Arrhenius equation?
ln k = -Ea/RT + ln A
What would be the X and Y axes on a graph that represents the Arrhenius equation? What would the gradient and the y-intercept represent?
X-axis = 1/T
Y-axis = ln k
Gradient = -Ea/R
y-intercept = ln A