Chemical Kinetics Concepts Flashcards
The study of reaction rates defined by the change in the concentrations of
reactants and products with time.
Chemical kinetics
Chemical kinetics is the study of reactions rates defined by the ______
change in the concentrations of reactants and products with time
describes the quantitative
relationships between the amounts of reactants present and the amounts of products
that can be formed,
Balanced chemical equation
balanced chemical equation for a reaction describes the quantitative
relationships between
the amount of reactants present and the amount of products that can be formed
True or False: Balanced chemical equations can sometimes indicate how fast a reaction will occur
False
Factors that affect reaction rates
Molecular orientation
Concentration
temperature
catalyst
pressure
surface area
reactant state of matter
Two substances cannot possibly react with each other unless _______
their
individual particles (molecules, atoms, or ions) come into contact.
If
there is no contact, the reaction rate will be ________
zero
the more particles collide per unit time, the __________.
the more a reaction between them
can occur.
the reaction rate usually ________ as the concentration of the
reactants increases.
increases
True or False: The more the reactant particles moving together, the more the molecules collide.
True
the more particles collide per unit time, _________________.
the more a reaction between them
can occur.
Consequently, the reaction rate usually _________ as the concentration of the
reactants increases.
increases
Relationship between temperature and average kinetic energy
Directly proportional
Increasing the temperature of a system ________ the average kinetic energy of its
individual particles.
Increases
What happens when the average kinetic energy increases
the particles move faster
and collide more frequently per unit time and possess greater energy when they collide.
the reaction rate of virtually all reactions decreases
with ________ temperature.
decreasing
Example of where temperature affects rate of reaction
refrigeration retards the rate of growth of bacteria
in foods by decreasing the reaction rates of biochemical
reactions that enable bacteria to reproduce.
True or False: Catalysts affect net chemical change itself
False: Catalysts increases the reaction rate without undergoing a net chemical change itself.
a substance that participates in a chemical reaction
Catalysts
The rate of a chemical reaction can be raised by
_______ the surface area of a solid reactant.
Increasing
If the surface area of a reactant is increased:
✓ more particles are exposed to the other reactant;
✓ the rate of reaction increases;
✓ there is a greater chance of particles colliding, which leads to more
successful collisions per second.
If the surface area is increased, more particles are _____ to the other reactant
exposed
What happens to the rate of reaction when there is an increase in the surface area
The rate of reaction also increases
What happens when the pressure of gaseous reactants is increased
the particles of the reactant for a given volume also increases.
The higher the pressure of reactants, the ___________
the rate of a reaction will be.
Faster
If the pressure of gaseous reactants is increased
there are more reactant
particles for a given volume.
The _________ the pressure of reactants, the faster the rate of a
reaction will be.
Higher
Expressed as the concentration of reactant consumed or the concentration
of product formed per unit time.
Reaction rate
units for reaction rate
moles per liter per unit time
The units are moles per liter per unit time, written as
M/s, M/min, or M/h.
is the change in
the concentration of either the
reactant or the product over a
period of time.
reaction rate
true or False: In systems where more than one reaction is possible, the
same reactants can produce different products under different
reaction conditions.
True
in the presence of dilute
sulfuric acid and at temperatures around 100°C, ethanol is
converted to ___________:
Diethyl ether
At 180°C, however, a completely different reaction
occurs, which produces _______ as the major product:
ethylene
Square brackets indicate _______
Molar concentration
the capital Greek delta (Δ) means “___________”.
change in
can be calculated from
the concentrations of either the reactant or one of the products at thebeginning of the interval (time = t0) and at the end of the interval (t1).
Average reaction time
The average reaction rate for a given time interval can be calculated
from the concentrations of either the reactant or one of the products at the beginning of the interval (time = t0) and at the end of the interval (t1).
Mathematical relationship between the chemical reaction and the
concentration of its reactants.
rate law
Rate law formula
RATE LAW = k [A]x[B]y
Reaction order: rate multiplied by 1
0
Reaction order: rate multiplied by 2
1st order
Reaction order: rate multiplied by 4
2nd order
Reaction order: rate multiplied by 1/2
-1
Rate constant: rate multiplied by 1
k
Rate constant: rate multiplied by 2
k[A]
Rate constant: rate multiplied by 4
k[A]^2
is simply the sum of orders for each
reactant.
overall reaction order
describe the mathematical
dependence of the rate on reactant concentrations.
reaction order
The reaction orders in a rate law describe the
mathematical
dependence of the rate on reactant concentrations.
is the instantaneous rate at the
start of the reaction (when t = 0).
initial rate
units on k if overall reaction order is 0
M/s
units on k if overall reaction order is 1
1/s
units on k if overall reaction order is 2
1/(M*s)
express the reaction rate as a function of the initial concentration and a measured (actual) concentration of one or more reactants after a specific amount of time (t) has passed;
Integrated rate laws
