Kinetics Flashcards
Kinetics
Temperature
Catalyst
Concentration
Kinetics
Rate at which chemical reactions occur Factors which affect rate Important Optimal rate Successful
Kinetics
Delta means a change in
Concentration only decreases with time
Only positive
Minus sign
Rate equations
K is the rate constant
Constant varies if temp or catalyst added
Orders of reaction
Zero order reaction
Doesn't depend on reactions In biology Enzyme is saturated Max rate Little difference Concentration of the reaction (substrate)
First order reaction
Concentration depends on one of the reactants
Second order reaction
Depends on concentration New rate is 4 times Old rate double Doubling concentration increase fold [a]1 shows first reaction A 2 shows second reaction
Cont
Orders of reaction found in exp
Gives info
Conc affects rate of reaction
Order gives info
Rate limiting step
Slow
Controlled
Overall reaction measures rate limiting step
Activation energy
Raised in energy reactants Transition states be covalent bonds Broken Rearrangement Breaking formation of covalent bonds
Rate limiting step
In an enzyme catalysed reaction will involve formation if transition state with highest activation energy
Equilibrium
Doesn’t complete exp
Products react together to reform
Reversible
At equilibrium the forward rate k1 is equal to the backward rare
Cont
Has different notations
Normal unit
Constant enzyme catalysed
Reduction of pyruvates happens in skeletal muscle
Cont
Each conpound present
First equation must be balanced
Balancing equations is stoichiometric coefficients u
Cont
Equations follow law of conversion
Same number of atoms of each element on both sides
Sttoichemistry
All quantitive aspects of chemical composition and reaction
Cont
The magnitude gives an idea if the equilibrium favours products or reactants v
The denominator will be bigger than numerator. Equilibrium is constant so less unity
Equilibrium postion can Chang
Can go in either direction
Towards products or reactants when stress happens.
Changing vol or pressure of gas phase or temp can increase or decrease amount of reactant or product
Cont
By adding high lactate, the enzymes which catalysed the reaction called lactate dehydrogenase.lavtate from muscle is disturbed from liver converting back to pyruvates
Cont
Equilibrium postion can change but the equilibrium constant is fixed at constant temp.
Free energy change of a reaction is related. Gives info process is feasible
Free energy change is 0 at equilibrium
Can be negative or positive delta
Cellular reactions are exergonic and generate a negative free energy.
Cells metabolic process reach equilibrium then cell dies
Analogous to a battery which has reached equilibrium
Summing up
Rates of reaction effected by temp, catalysed and conc if reactants
Expressed in conc with time Order of indicate the depency of reaction rate on conc
Summing up
Rate of reactions depends on rate limiting step
Reaction maybe reversible
Hugh value of equilibrium constant indicates the reaction lies in favour
Summing up
Le chateliers principle states that is a stress is placed in an equilibrium the equilibrium will shift in direction to relieve stress
Summing up
Changes in free energy o a reaction are related to the equilibrium constant for that reaction.
A reaction has 0 free energy change
