QUARTER 2 EXAM Flashcards
The area of chemistry concerned with speed, or rates, at which a chemical reaction occurs
CHEMICAL KINETICS
refers to the rate of a reaction, or the reaction rate, which is the change in the concentration of a reactant or a product with time (M/s)
Kinetics
Any reaction can be represented by the general equation:
Reactants → Products
The speed at which a chemical reacts is called reaction rate
A + B → C
THE RATE OF REACTION
__________ helps determine how reactions occur, specifically the order in which chemical bonds are broken or formed.
Chemical kinetics
Reactants typically _____ in concentration over time, while products ______.
decrease ; increase
The more readily molecules collide, the faster they react. Smaller particles with larger surface areas react faster.
In order to react, molecules must come in contact with each other
The more homogeneous the mixture of reactants, the faster the molecules can react
PHYSICAL STATE
FACTORS AFFECTING THE RATE OF REACTION
PHYSICAL STATE
REACTANT CONCENTRATION
REACTION TEMPERATURE
CATALYST
Higher concentration means more particles are available to collide, increasing the reaction rate.
As reactant concentration increases, the frequency with which the reactant molecules collide increase, leading rates
REACTANT CONCENTRATION
Increasing temperature raises kinetic energy, making particles move faster and collide more often.
Reaction rates generally increase as temperature is increased
REACTION TEMPERATURE
A _____ speeds up the reaction by changing the reaction mechanism but is not consumed in the process.
catalyst
For a reaction to occur:
Particles must _____
_________ to break bonds.
The correct _________ to form new bonds.
- collide
- Sufficient energy
- orientation
TRUE OR FALSE
The greater the number of collisions the slower the rate.
false
The greater the number of collisions the faster the rate.
true or false
The more molecules present, the greater the probability of collision and the faster the rate.
true
In order for reaction to occur the reactant molecules must collide in the correct orientation and with enough energy to form products
true or false
true
Reactant rates are denoted with a negative sign to show ______, while products are positive
depletion
At any specific time, the rate at which a reaction is proceeding is known as its ________
instantaneous rate.
The rate at one single/particular point in time
Instantaneous Rate
Rate calculated between 2 points.
: the average between 2 instantaneous reaction rates.
Average Rate:
A constant of proportionality between the reaction rate and concentration of reactant
RATE CONSTANT
It remains constant regardless of the time point; it does not change over the course of the reaction.
RATE CONSTANT
The exponents x and y specify the relationships between the concentrations of reactants A and B and the reaction rate.
RATE LAW
For any reaction, the rate law must be determined experimentally
true or false
true
A _______reaction is one whose rate depends either on a reactant concentration raised to the second power on the concentrations of two reactants each raised to the first power
second-order
Rate expressions are not always determined by experiments
true or false
false
Rate expressions are always determined by experiments
It expresses the relationship of the rate of a reaction to the rate constant and the concentration so the reactants raised to some papers:
aA+bBcC+dD
rate law
A ______ reaction is one whose rate depends on the concentration of a single reactant raised to the first power
first-order
Rate depends on the concentration of one reactant
first order
Rate depends on the concentration of one reactant squared or two reactants
second-order
is one which rate of disappearance of A is independent of [A]
zero-order reaction
Rate is independent of the concentration of reactants
zero order
______ Order: The initial rate decreases eightfold when the concentration of the reactant is doubled (1:3 relationship).
Third
_____ Order: The initial rate quadruples when the concentration of the reactant is doubled (1:2 relationship).
Second
_____ Order: No effect on the initial rate when the concentration of the reactant is changed.
Zero
____ Order: The initial rate doubles when the concentration of the reactant is doubled (1:1 relationship).
First
The time required for the concentration of a reactant to reach half its initial value
THE HALF-LIFE (T ½)
A convenient way to describe how fast a reaction occurs
THE HALF-LIFE (T ½)
Drugs with _____ half-lives take longer to take effect but have prolonged action, allowing for less frequent dosing (e.g., once daily, weekly, or monthly).
longer
Drugs with _______ half-lives act quickly but wear off rapidly, necessitating multiple doses throughout the day.
shorter
Drugs reach a _______—where the amount of drug eliminated equals the amount administered—typically after five half-lives. This is crucial for maintenance medications (e.g., for hypertension, diabetes, and antibiotics).
steady state
Constant quantity per time
For every minute, 5mg of the drug is eliminated
THE HALF-LIFE: ZERO ORDER
The concentration of the reactant decreases by one-half in each of a series of regularly spaced time intervals, each interval equal to +½
THE HALF-LIFE: FIRST ORDER
It is used to calculate the remaining concentration of a substance after a given time period.
INTEGRATE RATE LAW: 1ST ORDER
Is the minimum amount of energy required for a chemical reaction to process. It is essentially a barrier that molecules overcome before they can react and form products.
ACTIVATION ENERGY