Unit 1: Reaction Kinetics Flashcards
The equation for rate is…
Change in amount of reactant or product/ change in time
Reaction kinetics is the study of…
The rate of reaction and the factors which effect the rate
Colour, temperature, pressure, mass, PH, conductivity, and concentration change are all examples of way you can measure…
Reaction rates
Name 7 examples of ways to measure reaction rates
Colour, temperature, pressure, mass, PH, conductivity, and concentration
Name six factors which effect the rate of a reaction
Temperature Concentration Surface area (heterogenous mixtures only) Pressure (gasses) Nature of reactants Catalysts and inhibitors
The lower the temperature the _____ the reaction rate
Slower
The greater the temperature the _____ the reaction rate
Faster
Chemical reactions only occur when…
Collisions have enough energy to cause the atoms to rearrange
Only particles whose kinetic energy _____ the threshold energy have enough kinetic energy to _____.
EXCEEDS
React
Molecules to the left of the threshold may collide, but these collisions will not lead to….
The formation of products
Some particles that exceed the energy threshold still do not react because…
Of improper collision geometry
At lower temperatures _____ molecules have enough _____ to collide and _____ exceed the threshold
Few
Kinetic energy
Few
At _____ temperatures the entire molecules distribution shifts _____ which cause _____ molecules to exceed the threshold
Higher
Right
More
What two things are needed for particles to collide effectively and produce products?
needs to succeed threshold energy and have favourable collision geometry
As the concentration of a reactant increases the likelyhood that reactant molecules will collide ____ which translates into an _____ in reaction rate
Increases
Increase
The equation of the ideal gas law is..
Pressure (KPa) x volume=
n (# of moles) x gas constant
(8.31 KPa • L/mol - K) x Temperature (°K)
Volume and pressure are _____ proportional
Inversely
A pressure increase is equivalent to increase in ____ of gases
Concentration
When pressure is increased so is the likelihood that reactant molecules will _____.
Collide
increase in concentration= increase in collision frequency= increase in reaction rate
Nature of reactants is a factor which effects reaction rate because…
Some reactants are naturally more reactive than others
Some reactants are naturally more reactive than others because of…
Their chemical properties and their bonds involved in the chemical reaction
The number and strength of ____ effects the reaction rate
Bonds
Surface area yields an increased reaction rate only when the reaction is _____.
Heterogenous (reaction where the reactants are in more than one phase)
Catalysts increase the rate of reaction. What is a catalyst?
Catalysts are chemicals which increase the rate of a chemical reaction without itself undergoing permanent chemical change in the process
Inhibitors slow the rate of reaction. What is a inhibitor?
Inhibitors are chemicals which decrease the rate of a chemical reaction without itself undergoing permanent chemical change in the process
Instantaneous rate is found by
Finding the slope of the line tangent to the curve
All reactions ____ ____ over time
Slow down
The best indicator of the rate of a reaction is the instantaneous rate near the _____ of the reaction
Begining
Energy is ____ when bonds are formed
Released
Collisions have a variety of ____
Energies
In chemical reactions bonds are…
Broken and new ones are formed
As temperature increases the particles… (3 things)
Move faster
Collide more often
Collide with more energy
Matter consists of
Moving particles
You need a _____ to have a reaction
Collision
Collisions provide the ____ required to break bonds
Energy
Most collisions ___(are/are not) successful
Are not
The minimum amount of energy required for reaction is called…
Activation energy (Ea)
Reactions cannot occur unless the molecule possesses….
Sufficient energy to get over the activation energy barrier
What does a reaction coordinate diagram show?
A reaction coordinate diagram shows the energy of the reactants and products as a reaction proceeds
The high points on a reaction coordinate diagram are the ____ _____. The species present at this point are called ____ ____
Tradition states
Activated complexes
The energy gap between the reactants and the activated complex is the ….
Activation energy barrier
If change in H is positive the reaction is _____
If the change in H is negative the reaction is _____
Endothermic
Exothermic
The _____ _____ is the actual sequence of steps which make-up the overall reaction
Reaction mechanism
Most reactions occur in ____ (1/>1 ) step
> 1
Most reaction require a sequence of steps
And elementary process is…
a one step reaction; only two particles involved
The slowest step in a reaction is…
The rate determining step
Almost any reaction having _____ reactant particles in a balanced equation will occur in more than one step
3 (or more)
Catalysts is a substance which provides an overall reaction with an _____ ____ which has a _____ activation energy
Alternative mechanism
Lower
When a catalyst is used the activation energy is lowered so more reactants will have enough kinetic energy to form _____ _____
Activated complexes
Catalysts increase the reaction rate for both the _____ and _____ reaction
Forward
Reverse
Phase effects the rate of reaction. Order the following phases from fastest reacting to slowest
Gasses/ liquids, solids, aqueous ions
Aqueous ions>gasses/liquids> solids
Out of the 6 factors which effect reaction rate which one does not apply to homogenous substances
Surface area
