Arrhenius Equation Flashcards
What is present in the Arrhenius equation?
Rate constant
Arrhenius constant
Activation energy
Gas constant
Temperature
What unit is temperature measured in?
Kelvin
Celsius to kelvin
+273
Arrhenius equation
_Activation energy/
Gas constant x temperature
Constant = Arrhenius constant x (exponential) ^
How can we simplify the Arrhenius equation?
Remove the exponential by taking the ln of both sides
Activation energy units
Joules
Simplified Arrhenius equation
ln(k) = ln(A) - Ea/RT
What happens to the rate constant when activation energy decreases?
The rate constant calculated will get bigger, so showing on the rate equation the rate of reaction increases
How does the equation show activation energy decreasing resulting in larger k value calculated?
the fraction Ea/RT will decrease thus smaller value is being taken away from Arrhenius constant so overall increase in rate constant
lnk = lnA - Ea/RT
Explanation for why decreasing Ea increases rate constant
Because more collisions between reactant particles will surpass the activation energy and therefore be successful, so higher proportion of successful collisions
Which increases rate of reaction so rate constant increases according to rate equation
Increasing temperature affect on rate constant
Increases rate constant because the rate of reaction increases
So on the rate equation, the rate constant increases to make up for it
How does the equation show temperature increasing resulting in a larger value of k?
lnk = lnA - Ea/RT
Increasing T means a smaller fraction taken away from Arrhenius constant
So the value of k will be larger
Explanation for why increasing temperature increases the value of k?
Increasing temperature increases the kinetic energy of reactant particles
So a greater proportion of collisions between reactant molecules are of sufficient energy to overcome the activation energy thus increases proportion of successful collisions
Increase rate of reaction increases rate constant as a result:)
Explanation for why increasing temperature increases the value of k?
Increasing temperature increases the kinetic energy of reactant particles
So a greater proportion of collisions between reactant molecules are of sufficient energy to overcome the activation energy thus increases proportion of successful collisions
Increase rate of reaction increases rate constant as a result:)
Rearrange equation to calculate activation energy
Activation energy = RT x (lnA -lnk)
Ensure you use the natural log function of calculator of the Arrhenius constant and rate constant
ENSURE YOU CALCUKATE BRACKETS VALUE FIRST
