chemistry

Chemical Kinetics Home > Physical & Theoretical Chemistry > Chemical Kinetics CHEMICAL KINETICS Rate of chemical reaction - Chemical Kinetics Rates of a chemical reaction and the Collision Model How to determine the order of a reaction by the Initial Rates method   Chemical kinetics is the area of chemistry concerned with the rates (speeds) of reactions . It explains how the rates of different chemical reactions vary over an enormous range of time scales (seconds to years). The main goals of chemical kinetics is to understand the following: The factors that control reaction rates Establish relationships between the rate of a reactions and the amount of reactants present Understand the steps by which a reaction occurs (mechanism of reaction) Optimize conditions to carry out chemical reactions at reasonable rates under proper contro...

How to determine the order of a reaction? Determining the form of the Rate Law (Order of Reaction) by the method of Initial Rates Home > Rate of a Chemical Reaction - Chemical Kinetics > Rates of Chemical Reactions and the Collision Model > How to determine the order of a reaction by the initial rates method?   How to determine the order of a reaction by the initial rates method?   A rate law is an expression which shows how the rate of a reaction depends on the concentrations of reactants. For the decomposition of NO 2 we can write: 2NO 2 (g) → 2NO(g) + O 2 (g)  Rate = k [NO 2 ] n      (Rate Law) k is the rate constant and n is the order of reaction (n can be positive or negative, integer or fraction) Both k and n must be determined experimentally. For the general reaction: aA + bB → cC + dD   (1) the rate law is given by:   Rate = k. [A] m [B] n     (2)   There are two types of rate laws: The differential rat...

rates of chemical reactions and the collision model Home > Rate of a Chemical Reaction - Chemical Kinetics > Rates of Chemical Reactions and the Collision Model   Rates of Chemical Reactions and the Collision Model   Reaction rates are affected both by reactant concentrations and by temperature . The collision model , that is based on the kinetic-molecular theory , explains for both of these effects at the molecular level. In general only a small number of reactant collisions leads to products (in certain cases 1 in 10 13 collisions). The basic principles of the collision model (collision theory) are as follows: Molecules must collide to react – Collisions are necessary to transfer kinetic energy, to break reactant chemical bonds and form product bonds The greater the number of collisions per second the greater the reaction rate – This agrees with the observation that as reactant concentration increases the rate of a reaction...

Rate of a Chemical Reaction Home > Rate of a Chemical Reaction - Chemical Kinetics   Rate of a Chemical Reaction - Chemical Kinetics Chemical kinetics is the area of chemistry in which reaction rates are studied. Kinetics is largely an experimental science. Reaction rate is called the speed at which a chemical reaction occurs. Some chemical reactions are complete within a fraction of a second (explosions) while others take years (corrosion of metals) or even centuries (formation of mineral’s in Earth). The basic concepts covered in this post are the following: Factors that affect the rate of chemical reactions Definition of the rate of reaction   What are the factors that affect the rate of chemical reactions? Four factors allows us to change the rate at which a reaction occurs:   Physical state and nature of the reactants Reactants in the same physical state tend to react faster since there is a greate...