Kinetics II Flashcards
(27 cards)
What is the general form of a rate equation?
Rate = k[A]m[B]n where m and n are the orders of reaction with respect to reactants A and B
What is activation energy?
The minimum amount of energy required for a reaction to occur
What must particles do for a reaction to occur?
Particles must collide, possess activation energy, and approach with the correct orientation
List methods to increase the rate of reaction.
- Increase the temperature
- Increase the surface area of solids
- Increase the concentration of reactants
- Increase the pressure of gases
- Add a catalyst
- Shine a light
How does the concentration of reactants change over time during a reaction?
Concentration of reactants decreases while the concentration of products increases
What does the slope of the concentration vs. time curve represent?
The rate of reaction; the slope gets less as the reaction proceeds
What is the initial rate of reaction?
The slope at the start of the reaction
What is the significance of the rate equation?
It links the rate of reaction to the concentrations of the reactants
What does the order of reaction indicate?
How much the concentration of a reactant affects the rate of reaction
What is the overall order of reaction?
The sum of all the individual orders of a rate equation
What is the order with respect to a reactant if it does not affect the rate of reaction?
Zero order
What is the initial rate method in determining reaction order?
A method where experiments are conducted by changing the concentration of only one reactant at a time
How can the order with respect to a reactant be determined graphically?
Using rate-concentration graphs to observe the relationship between concentration and rate
What does a horizontal line in a rate-concentration graph indicate?
Zero order with respect to that reactant
What does a straight line through the origin in a rate-concentration graph indicate?
First order with respect to that reactant
What happens to the rate constant k when temperature increases?
k always increases when the temperature is increased
What is the rate-determining step?
The slowest step in a multi-step reaction that controls the overall rate
Why might a reactant not appear in the rate equation?
It may not be involved in the rate-determining step or its concentration does not affect the rate
Define the units of the rate constant k for a second-order reaction.
dm^3 mol^-1 s^-1
What is the effect of a catalyst on the rate of reaction?
It lowers the activation energy and increases the rate of reaction
What is the relationship between concentration and rate for a first-order reaction?
Rate is directly proportional to the concentration
What is the relationship between concentration and rate for a second-order reaction?
Rate is proportional to the square of the concentration
Fill in the blank: The rate equation can only be determined from _______.
experimental data
List the structural isomers of C4H9Br.
- 1-bromobutane
- 2-bromobutane
- 2-bromo,2-methylpropane
These isomers differ in the arrangement of atoms
