CHE 002C Kinetics

Average Rate of disappearance

Rate = -Delta[A] / Delta T

Reaction Rate

-(1/a)( Delta[A] / Delta T ) = (1/b)( Delta[B] / Delta T )

Initial Rates method

Finding the rate constant K and order numbers from experimental data.

First order Integrated Rate Law

ln[A] = -kT + ln[A]0

First order plot and slope

ln[A] vs T where K = -slope

First order Half-Life

t ½ = 0.693/K , where its half life is constant and independent of initial concentration.

2nd order Integrated Rate Law

1/ [A] = kT + 1/ [A]0

Second Order Plot and Slope

1/ [A] vs t where slope = K

2nd Order Half Life

t ½ = 1 k[A]0 where half life increases as concentration drops

Zero Order Integrated Rate Law

[A] = -kT + [A]0

Zero order Half Life

t ½ = [A]0 / 2K where half life decreases as concentrations drops

Zero order Plot and Slope

[A] vs t where slope = -K

Pseudo first-order law

Where concentration differs greatly so, k[A][B] becomes k’[A] and k’ is (k[B]).

Intermediate

molecule formed and consumed in reaction mechanisms

Molecularity

Using reactant to determine rate law.

Two requirements to be a correct reaction mechanism

Sum of steps equal overall reactions, RDS rate law matches experimental rate law.

Rate determining step (RDS)

slowest step determines overall reaction rate

Activation Energy (Ea)

energy to overcome for reaction

Arrhenius equation for graph data y=mx+b

ln(K) = (-Ea/R)(1/T) + ln(A)

Arrhenius graph and slope

lnK vs 1/T where slope = -Ea/R

Arrhenius equation with two points

ln(K2/K1)= (Ea/R)(1/T1 - 1/T2)

Catalysts

speed up reactions, decrease Ea, with ought being consumed.

Ammonia NH3 Production catalysts

Fe and FeO, or now (Fe + K + Ca)

Sulfuric Acid H2SO4 catalysts

Pd

CO2 byproduct of kerns cycle catalyst.

Carbonic anhydrase

Heterogenous Catalysts

Catalyst (solid) in different phase than reactants

Hydrocarbon catalysts

Pd, Pt

Human Produces SO2 catalyst

Dust, it also caused acid rain when react with water

Catalytic converter catalyst

Pd, Pt. converts unburned car fuel

Homogenous Catalyst

Catalyst in same phase as reactants

NO unusal effects

In lower atmosphere: NO catalyses O2 —> O3, in upper atmosphere: NO catalyses O3 —> O2+NO2 causing greenhouse

Freons catalyst

Freons emit Cl byproduct, which then makes ClO and depletes ozone.

Acid Catalysts

reactant gains H+ from Acid and becomes attracted to lone pairs.