<–2/”>a >Chemical kinetics
Chemical kinetics is that branch of chemistry which deals with the study of the speeds or the rates of chemical reactions, the factors affecting the rates of the reactions and the mechanism by which the reactions proceed. It concerns itself with the measurement of rates of reactions proceeding under the given conditions of temperature, pressure and concentration.
Chemical Reactions are classified into following on the Basis of Rate of Reaction :- 1. Fast/instantaneous reactions :-It is practically impossible to measure the speed of such reactions, e.g., ionic reactions. organic substitution reactions. 2. Slow reactions Chemical re actions which completes in a long time from some minutes to some years are called slow reactions. e.g., rusting of iron. transformation of diamond etc. 3. Moderately slow reactions Chemical reactions which are intermediate between slow and fast reactions are called moderately slow reactions.
Chemical Reaction rates are the rates of change in concentrations or amounts of either reactants or products.The rate of a reaction depends on the concentration of reactants. As the reaction proceeds the reactants get consumed and their concentration decreases with time. Therefore, the rate of reaction does not remain constant during the entire reaction.
Various Factors Affecting Rate of Reaction are:-
- Nature and concentration of reactant :-Generally the rate of a reaction increases as the concentration of the reactants is increased.
- Temperature :-A reaction is faster when the reaction temperature is increased.
- Surface area of reactant
- Radiations and Catalyst
- Pressure of gas
- Presence of a Catalyst:-A catalyst alters the reaction rate without being consumed by the reaction.
Rate law is defined as the mathematical relationship between rate of a reaction and the concentration of the reactants.
x y rate = k [A] [B]
Half-life is the time taken for the concentration of a reactant to drop to half its original value. In a first-order chemical reaction, the half-life of the reactant is ln(2)/?, where ? is the reaction rate constant.,
Chemical kinetics is the study of the rates of chemical reactions. It is a branch of physical chemistry that deals with the rates of chemical reactions, the factors that affect them, and the mechanisms by which they occur.
The Rate of a Chemical Reaction is the change in the concentration of a reactant or product per unit time. The rate law is an equation that expresses the rate of a chemical reaction in terms of the concentrations of the reactants and products. The order of a reaction is the power to which the concentration of each reactant is raised in the rate law. The rate constant is a constant that appears in the rate law and is characteristic of the reaction.
The temperature dependence of the rate constant is given by the Arrhenius equation, which states that the rate constant is proportional to the exponential of the negative of the activation energy divided by the temperature. The activation energy is the energy required to form the activated complex, which is an intermediate state in the reaction mechanism.
Catalysis is the process by which a substance increases the rate of a chemical reaction without itself undergoing any permanent chemical change. Catalysts can be either homogeneous or heterogeneous. Homogeneous catalysts are in the same phase as the reactants, while heterogeneous catalysts are in a different phase.
Elementary reactions are reactions that occur in a single step. Complex reactions are reactions that occur in multiple steps. The steady state approximation is a mathematical technique that is used to simplify the analysis of complex reactions.
Collision theory is a theory that explains the rates of chemical reactions in terms of the frequency of collisions between Molecules and the Probability that a collision will result in a reaction. Transition state theory is a theory that explains the rates of chemical reactions in terms of the energy required to form the activated complex.
Reaction mechanisms are the detailed steps by which a chemical reaction occurs. Reaction coordinate diagrams are diagrams that show the energy changes that occur during a chemical reaction. Kinetic isotope effects are effects on the rate of a chemical reaction that are caused by the use of different isotopes of the same element.
Pre-equilibrium approximations are mathematical techniques that are used to simplify the analysis of complex reactions that involve pre-equilibrium steps. Non-Arrhenius kinetics is the study of chemical reactions that do not obey the Arrhenius equation.
Chemical reaction networks are networks of chemical reactions. Chemical reaction systems are systems of chemical reactions that are coupled to each other. Chemical reaction engineering is the application of chemical kinetics to the design and operation of chemical reactors.
The following are some of the applications of chemical kinetics:
- The development of new drugs and other pharmaceuticals.
- The design of industrial processes.
- The study of environmental pollution.
- The study of combustion processes.
- The study of biological processes.
Chemical kinetics is a complex and fascinating field of study. It is essential for understanding the rates of chemical reactions and the factors that affect them. It is also essential for the design and operation of chemical reactors.
What is chemical kinetics?
Chemical kinetics is the study of the rates of chemical reactions. It is a branch of physical chemistry that deals with the rates of chemical reactions and the factors that affect them.
What are the different types of chemical reactions?
There are four main types of chemical reactions:
- Synthesis reactions are reactions in which two or more reactants combine to form a single product.
- Decomposition reactions are reactions in which a single reactant breaks down into two or more products.
- Single-displacement reactions are reactions in which one element replaces another element in a compound.
- Double-displacement reactions are reactions in which two compounds exchange ions to form two new compounds.
What are the factors that affect the rate of a chemical reaction?
The rate of a chemical reaction is affected by several factors, including:
- The concentration of the reactants: The higher the concentration of the reactants, the faster the reaction will occur.
- The temperature: The higher the temperature, the faster the reaction will occur.
- The presence of a catalyst: A catalyst is a substance that speeds up the rate of a chemical reaction without being consumed by the reaction.
- The surface area of the reactants: The larger the surface area of the reactants, the faster the reaction will occur.
What is the law of mass action?
The law of mass action states that the rate of a chemical reaction is proportional to the product of the concentrations of the reactants raised to the power of their stoichiometric coefficients.
What is the rate law?
The rate law is an equation that expresses the relationship between the rate of a chemical reaction and the concentrations of the reactants.
What is the order of a reaction?
The order of a reaction is the sum of the powers to which the concentrations of the reactants are raised in the rate law.
What is the activation energy?
The activation energy is the minimum amount of energy required for a chemical reaction to occur.
What is a transition state?
A transition state is an unstable intermediate state that forms during the course of a chemical reaction.
What is a reaction coordinate diagram?
A reaction coordinate diagram is a graph that shows the potential energy of a system as a function of the reaction coordinate. The reaction coordinate is a measure of how far the reaction has progressed.
What is a mechanism?
A mechanism is a step-by-step description of how a chemical reaction occurs.
What is a collision theory?
Collision theory is a theory that explains the rate of chemical reactions in terms of the frequency of collisions between reactant molecules and the energy of the collisions.
What is a steady state approximation?
The steady state approximation is a mathematical technique that is used to simplify the rate law for a chemical reaction.
What is a pre-equilibrium?
A pre-equilibrium is a fast equilibrium that occurs before the rate-determining step of a chemical reaction.
What is a unimolecular reaction?
A unimolecular reaction is a reaction in which one reactant molecule decomposes to form two or more products.
What is a bimolecular reaction?
A bimolecular reaction is a reaction in which two reactant molecules collide to form a product.
What is a termolecular reaction?
A termolecular reaction is a reaction in which three reactant molecules collide to form a product.
What is an elementary reaction?
An elementary reaction is a reaction that occurs in a single step.
What is a complex reaction?
A complex reaction is a reaction that occurs in multiple steps.
What is a chain reaction?
A chain reaction is a reaction in which the products of the reaction themselves participate in the reaction.
What is a radical reaction?
A radical reaction is a reaction that involves free radicals.
What is a concerted reaction?
A concerted reaction is a reaction that occurs in a single step without any intermediate steps.
What is a pericyclic reaction?
A pericyclic reaction is a reaction that involves a cyclic transition state.
What is a sigmatropic reaction?
A sigmatropic reaction is a pericyclic reaction in which a sigma bond is shifted to another position in the molecule.
What is a suprafacial reaction?
A suprafacial reaction is a sigmatropic reaction in which the migrating group moves over the top of the Ï system.
What is an antarafacial reaction?
An antarafacial reaction is a sigmatropic reaction in which the migrating group
1. Which of the following is not a factor that affects the rate of a chemical reaction?
(A) Temperature
(B) Concentration
(C) Pressure
(D) Catalyst
2. The rate of a chemical reaction is the change in concentration of a reactant or product per unit time.
(A) True
(B) False
3. The rate of a chemical reaction can be increased by increasing the temperature.
(A) True
(B) False
4. The rate of a chemical reaction can be increased by increasing the concentration of the reactants.
(A) True
(B) False
5. A catalyst is a substance that increases the rate of a chemical reaction without being consumed by the reaction.
(A) True
(B) False
6. The rate of a chemical reaction can be decreased by decreasing the temperature.
(A) True
(B) False
7. The rate of a chemical reaction can be decreased by decreasing the concentration of the reactants.
(A) True
(B) False
8. The rate of a chemical reaction is not affected by the pressure.
(A) True
(B) False
9. The rate of a chemical reaction is affected by the surface area of the reactants.
(A) True
(B) False
10. The rate of a chemical reaction is affected by the presence of a catalyst.
(A) True
(B) False