2: entropy, gibbs, kinetic theories, gases Flashcards
thermodynamically favored
spontaneous, expexted
not thermodynamically favored
non-spontaneous, unexpected
what is entropy?
measured randomness/disorder of a system
what states have the most entropy?
solid<liquid«gas
what increases entropy?
- increases temp
- dissolving
- increases time
what is a state function
properties that remain the same regardless the path
sign of entropy if there is more gas mols on the reactants side?
∆S < 0 , less gas = less entropy
sign of entropy if there is more gas mols on the products side?
∆S > 0
∆G > 0
NOT spontaneous
∆G < 0
spontaneous
∆G = 0
at equilibrium
Gibbs table?
∆H ∆S -T∆S ∆G
- + - always TF
- - + - at low, + at high
+ + - + at low, - at high
+ - + never T.F
Kinetic Molecular Theory of gases
- The particles are in constant, random motion.
- The combined volume of the particles is negligible.
- The particles exert no forces
- Collions are elastic.
- The average kinetic energy of the particles is proportional to the temperature in kelvin
Does a larger mass mean more or less velocity?
Larger mass = less velocity
What two conditions must be achieved to successfully produce products?
- Particles must collide with a certain amount of energy, called activation energy (Ea)
- Particles must collide with the proper geometry or
orientation
Maxwell-Boltzmann Distribution
Shows the distribution of the kinetic energies of particles at a given temperature
longer/shallower curve = hotter
Is ∆H changed by a catalyst?
No
What is the activated complex (AC)
The transition state, the top of the peak in a graph
What does a catalyst do?
Increases rate of reaction, decreases activation energy
What is the rate determining step
The slowest step
How to identify catalysts and intermediates in a reaction
- catalyst reacts in step 1 and is a product in step 2
- intermediate reacts in step 2 and is a product in step 1
What factors affect rate of reaction
temperature, concentration (more molecules = more collisions), surface area (smaller particles = increased rate), catalysts
rate law
rate = k (A) ^m (B) ^n
how to find k?
plug and chug concentrations into rate law expression
units of k for ‘n’ reaction order
1/M ^n-1 x S
how to find exponent
m = ln(left) / ln (right)
