Chapter 5 Flashcards
chemical kinetics
the study of reaction rates, the effects of reaction conditions on these rates, and the mechanisms implied by such obervations
Gibb’s free energy
delta G
value that determines whether a reaction is spontaneous or nonspontaneous
chemical mechanisms
these propose a series of steps that make up the overall reaction
often involves much more than is shown in just the chemical equation
intermediates
molecules that exit within the course of a reaction but ar neithr reactants nor products overall
rate determining step
the slowest step of a proposed reaction mechanism
collision theory of chemical kinetics
- for a reaction to occur, molecules must COLLIDE with each other
- the reaction rate is proportional to the number of effective collisions per second between the reacting molecules
what is meant by an effective collision
not all collisions result in a chemical reaction
an effectie collision is one in which the molecules collide in the proper orientation and have sufficient kinetic energy to break existing bonds and form new ones
activation energy (energy barrier)
the minimum energy of collision necessary for a reaction to take place
arrhenius equation
a mathematical representation of collision theory
transition state theory
Molecules form a transition state (activated complex) during a reaction
old bonds are partially dissociated while the new bonds are partially formed
greatest energy
free energy diagram
shows the relationship between activation energy, the free energy of the reaction, and the free energy of the system
exergonic reactions
energy is released; spontaneous
endergonic reactions
energy is absorbed
non spontaneous
factors that affect reaction rate: reactant concentrations
when reactant concentrations increase, reaction rate increases
factors that affect reaction rate: temperature
when temperature increases, reaction rate increases
