exam 2 ch 14 Flashcards
the half life is time required for
concentration of a reactant to fall from one-half of its original value
for half-life first order it is
independent of the initial concentration of the reactants
zeroth half life, lower the initial concentration of the reactants
the shorter the half life
second order half-life is
inversely proportional to the initial concentration
the arrhenius equation, reaction rate ordinarily
increases with temperature
collision theory
reactants (atoms, molecules, ions etc.) must collide in order to react with each other
why collision doesn’t always lead to reaction (1)
molecules must be oriented properly when they collide
why collision doesn’t always lead to reaction (2)
molecules must have adequate kinetic energy to react
molecules must have adequate kinetic energy to react bc
KE supplied must be high enough to break the chemical bonds and molecules with small KE just bounce off and don’t react
activation energy is
the kinetic energy required to break the chemical bonds
Collison theory (2) for a reaction to occur
reactants must come together with enough energy and proper orientation to react
number of collisions is dependent on
the number of gas particles in the system
increasing the amount of reactants
increases the total amount of collisions
increasing the temperature cause and results in
molecules to move faster
more collisions and a higher rate of reaction
temp is a measure of
average kinetic energy of molecules
higher the temp
the larger the fraction of molecules with kinetic energies equal to or greater than the activation energy (higher kinetic energy)
larger fraction of molecules possessing activation energy
a larger fraction of collisions leads to product formation (higher reaction rate)
potential energy diagrams show
the change in potential energy as reactants are converted into products
reactants to products
exothermic (change in H)
products to reactants
endothermic (change in H)
activation energy is the minimum energy
necessary to form a product during a collision btw reactants
activation energy is the height
of the hill btw the reactants and the products
higher the activation energy
slower the reaction rate
activated complex/transition state is the
high energy intermediate state (reactants and products have to go through)
the rate constant is dependent on
activation energy of reaction and temp
frequency factor is reaction specific
and takes care of fraction of collisions that have proper orientation and frequency
