13. Kinetics Flashcards
(21 cards)
Result of industrial exposure, air/water pollution, foods, medicines, improperly coated food containers, or ingestion of lead-based paints
Heavy metal poisoning
Bonding of ions and molecules to metal ions
Chelation
Medical procedure in clinical toxicology - administration of chelating agents to remove heavy metals from body (mercury, arsenic, lead)
Chelation therapy
Colourless to brown, [N2O5] decrease
Colour change from N2O5 to NO2
Reaction rate =
Δconcentration / Δtime
Units of reaction rate
M/s or mol/Ls
(Rate law) rate =
k[A]^m[B]^n
Components of the rate law can only be determined
experimentally
Overall reaction order =
m+n, sum of exponents in rate law
First-order reactions (2 pt)
- 1/2 life is independent of initial concentration
- straight line plot of ln[A]..t over t
Second-order reactions (2 pt)
- 1/2 life = t..1/2 = 1 / k[A]..0
- straight line plot of 1/[A]..t over t
Zeroth-order reactions (3 pt)
- Rate = k
- 1/2 life depends on [A..0]
- straight line plot for [A]..t over t
Sequence of elementary steps that shows the pathway from reactants to products
Reaction mechanism
Number of reactant molecules in a certain step of a pathway
Molecularity
Entity which is formed and used up during the reaction - does not appear in overall reaction
Reaction intermediate
Slowest elementary reaction, its rate law represents the rate law of the overall reaction
Rate-Determining step
Factors which affect reaction rate
Collision frequency, activation energy, molecular structure
Unstable species formed from an effective collision ‘between’ the reactant and product (not an intermediate)
Activated complex / transition state
Catalyst vs Intermediate
Catalyst: present at beginning of reaction, reappears at the end
Intermediate: only present during reaction
Exists in solution with reaction mixture (ex. production of vinegar uses a homogeneous catalyst)
Homogeneous catalyst
Exists as a different phase form the reaction mixture (ex. catalytic converter in car)
Heterogeneous catalyst
