Chapter 5.2 Flashcards
How are the order of a chemical reaction determined?
- they are determined experimentally
- >do not just look at the stoichiometric coefficients
What are the two conditions when stoichiometric coefficients match the order of a reaction
1) When the reaction mechanism is a single step
- >balanced overall step is reflective of the entire chemical process
2)Complete reaction mechanism is given and the rate determining step is indicated
What is the difference between equilibrium constant expression(Keq) and the rate law
Rate law
- > the expression for the rate law only includes the reactants
- > indicates how quickly an expression will get to equilibrium
Equilibrium constant expression
- > indicates where the reaction’s equilibrium position lies
- > includes the concentrations of all the species in the reaction(both products and reactants)
Describe the characteristics of a zero-order reaction
- one in which the formation of product C is independent of changes in the concentrations of reactants A and B
- these reactions have a constant reaction rate equal to the rate constant
What are ways to change the rate constant of a zero order reaction
- change the temperature
- or add a catalyst
- > reduce the activation energy
- > increase the value of k
Describe the characteristics of a first order reaction
- has a rate that is directly proportional to only one reactant
- > therefore, doubling one reactant concentration results in doubling of the rate formation of the product
- note molecule undergoes a chemical change all by itself
- > usually without the physical interaction with any other molecule
Describe the characteristics of a second order reaction
- it has a rate that is proportional to either the concentrations of two reactants or to the square concentration of a single reactant
- often occurs because of a collision between two reactants
How can one define mixed order reactions
-reactions that change order over time
