KINETICS Flashcards
Describe molecular motion in a solid
vibration about mean lattice position
IDEAL GAS eqn
PV=nRT
Describe molecular motion in a gas
constant, rapid, straight line motion, colliding frequently
Describe gaseous collisions
ELASTIC - no kinetic energy is lost/gained
A typical gas at 1 atm & 25 C consists of molecules travelling at __m/s and a collision occurs within _ ns
500
1
Viscosity ____ as temp. _____ due to ____ ______ energy
Viscosity decreases as temp. increases due to more kinetic energy
Ions move through solvent by application of ____ ______
Ions move through solvent by application of potential difference
RANDOM WALK MODEL
describes diffusion:
A force which represents the spontaneous tendency of molecules to disperse to a situation of greater disorder (entropy)
Fick’s Law
Diffusion is greater with a steeper concentration gradient.
Potential energy
molecular energy due to position
Kinetic energy
energy due to motion
how is kinetic energy distributed (motions)?
Rotation
Translation
Vibration
Rate of reaction depends on
COLLISION FREQUENCY
Fraction with sufficient energy
Fraction with correct ORIENTATION
Physical state: SAME PHASE reactants
Conc (collision freq)
Temp. (kinetic E)
Catalysts (Ea)
State general rate law
rate = k[A]n[B]m
Arrhenius equation
k=Ae(^Ea/RT)
State 3 ways how catalysts work
Activate reactant TM chemistry
Stabilise transition state
Different reaction mechanism
3 ways to measure rate
gaseous
spectrophotometric
conductivity
KINETICS
study of rates of reactions
ORDER of reaction
sum of exponents of concs in rate law
first order differential rate law
rate = k[A]
first order RDS
Carbocation formation
Only alkyl dependent
first order integrated rate law
ln[A] = ln[A]0 - kt
Sketch a ln conc-time graph
SLOPE = -k
First order half life
t(1/2) = 0.693/k
