Full Report On Chemical Equilibrium
CHEMICAL EQUILIBRIUM
I. Introduction In a chemical reaction, when reactants are mixed together in a reaction vessel, the whole of the reactants do not get converted into products. After some time, there will come a point when a fixed amount of reactants will exist in harmony with a fixed amount of products; neither amount will change anymore. This state is called chemical equilibrium (Birk, 1994; Jones, 1987; LeMay, 2002). There are three characteristics of a system in chemical equilibrium: a. the rates of the forward and reverse reactions are equal; b. the system does not undergo any observable changes; c. the system is closed (Freemantle, 1995). The concept of chemical equilibrium was developed after Berthollet (1803) found out that some chemical reactions are thermodynamically reversible. A system in equilibrium can be considered in the general equation: aA + bB +… ↔ dD + eE +… where the rates of the forward and backward reactions have to be equal. The “harpoon” arrows pointing both ways indicate equilibrium; A and B are the reactant chemical species; D and E are the product species; and a, b, d, and e are the stoichiometric coefficients.
It is possible to show experimentally that at equilibrium
Keq = [D]d[E]e [A]a[B]b where brackets represent the concentration and Keq denotes the equilibrium constant. This so-called Law of Mass Action was proposed by Norwegian chemists, Cato Maximilian Guldberg and Peter Waage (1865). They showed that an equilibrium can be approached from either direction, implying that any reaction aA + bB +… ↔ dD + eE +… is really a competition between a “forward” and “reverse” reaction: rate of forward reaction = rate of reverse reaction
Kf[A]a [B]b = Kr[D]d [E]e When a reaction is at equilibrium, the rates of these two reactions are identical. The K’s are called rate constants and the quantities in square brackets represent concentrations (Mortimer, 1986). In relation with
I. Introduction In a chemical reaction, when reactants are mixed together in a reaction vessel, the whole of the reactants do not get converted into products. After some time, there will come a point when a fixed amount of reactants will exist in harmony with a fixed amount of products; neither amount will change anymore. This state is called chemical equilibrium (Birk, 1994; Jones, 1987; LeMay, 2002). There are three characteristics of a system in chemical equilibrium: a. the rates of the forward and reverse reactions are equal; b. the system does not undergo any observable changes; c. the system is closed (Freemantle, 1995). The concept of chemical equilibrium was developed after Berthollet (1803) found out that some chemical reactions are thermodynamically reversible. A system in equilibrium can be considered in the general equation: aA + bB +… ↔ dD + eE +… where the rates of the forward and backward reactions have to be equal. The “harpoon” arrows pointing both ways indicate equilibrium; A and B are the reactant chemical species; D and E are the product species; and a, b, d, and e are the stoichiometric coefficients.
It is possible to show experimentally that at equilibrium
Keq = [D]d[E]e [A]a[B]b where brackets represent the concentration and Keq denotes the equilibrium constant. This so-called Law of Mass Action was proposed by Norwegian chemists, Cato Maximilian Guldberg and Peter Waage (1865). They showed that an equilibrium can be approached from either direction, implying that any reaction aA + bB +… ↔ dD + eE +… is really a competition between a “forward” and “reverse” reaction: rate of forward reaction = rate of reverse reaction
Kf[A]a [B]b = Kr[D]d [E]e When a reaction is at equilibrium, the rates of these two reactions are identical. The K’s are called rate constants and the quantities in square brackets represent concentrations (Mortimer, 1986). In relation with
Bibliography: Birk, J.P. 1994. Chemistry. Boston: Houghton-Mifflin Company Freemantle, M. 1995. Chemistry in Action. 2nd ed. London: McMillan Press. Jones, M. M. 1987. Chemistry and Society. 5th ed. Philadelphia: Saunders College Publishing. LeMay, E.H., Jr. 2002. Chemistry: Connection to Our Changing World. Massachusetts: Prentice- Hall, Inc. Redmore, F. H. 1980. Fundamentals of Chemistry. New Jersey: U.S Prentice-Hall, Inc. Tro, N. J. 2003. Introductory Chemistry. New Jersey: Pearson Education, Inc. Mortimer, C. E. 1986. Chemistry. 6th ed. California: Wadsworth Publishing Company.