REPUBLICA BOLIVARIANA DE VENEZUELA MINISTERIO DEL PODER POPULAR PARA LA EDUCACION SUPERIOR INSTITUTO UNIVERSITARIO POLITECNICO SANTIAGO MARIÑO MERIDA – MERIDA
CHEMICAL EQUILIBRIUM TEACHER: ARACELIS
STUDENT ALDRY GARCIA CI 22685488 ING QUIMICA
E X P L A I N T H E D Y N A M I C N AT U R E OF CHEMICAL EQUILIBRIUM AND CLASSIFY THE DIFERENT TYPES OF EQUILIBRIUM CHEMICAL Reactions in nature often do not reach completion.In most reactions two or more substances react to form products which themselves react to give back the original substances. Thus, two reactants, A and B may react to form C and D. The products C and D react again to form the reactants A and B. A+ B → C + D A reaction which can go in the forward and backward direction simultaneously is called a reversible reaction. The state of a reversible reaction is achieved when the two opposing reactions occur at the same rate and the concentrations of reactants and products do not change with time and is found to be in chemical equilibrium.
The chemical equilibria are classified into two types: 1) Homogeneous equilibrium and 2) Heterogeneous equilibrium. 1)Homogeneous equilibrium: A chemical equilibrium is said to be homogeneous if all the substances (reactants and products) at equilibrium are in the same phase 2) Heterogeneous equilibrium: A chemical equilibrium is said to be heterogeneous if all the substances at equilibrium are not in the same phase.
E X P R E S S T H E FA C T O R S A F F E C T I N G T H E CHEMICAL EQUILIBRIUM Changes in Concentration According to Le Chatelier's Principle, the addition of product or the removal of reactants to a system will shift the equilibrium towards the reactants, while the addition of more reactants or the removal of product will provide the opposite shift towards product, or the right-hand side of the reaction equation. This can be illustrated by the equilibrium of carbon monoxide and hydrogen gas, reacting to form methanol.
Changes in Pressure A change in pressure (or volume) will result in an attempt to restore equilibrium by creating more or less moles of gas. For example, if the pressure in a system increases (or the volume decreases), the equilibrium will shift to favor the side of the reaction that involves fewer moles of gas. Similarly, if the volume of a system increases (or the pressure decreases), the production of additional moles of gas will be favored.
Changes in Temperature Finally, increases in temperature will favor the reaction direction that consumes heat, while decreases in reaction temperature will favor the direction that produces heat. In other words, the addition of heat to an exothermicreaction will shift the equilibrium towards the reactants, while the same change will shift an endothermic reaction towards product formation. This can be viewed in the endothermic reaction of.Production of NO2 consumes heat.
I N T E R P R E T C A L C U L AT E E Q U I L I B R I U M C O N S TA N T S AND FREE ENERGY CHANGES The following equation relates the standard-state free energy of reaction with the free energy of reaction at any moment in time during a reaction (not necessarily at standard-state conditions): G = free energy at any moment G = standard-state free energy R = ideal gas constant = 8.314 J/mol-K T = temperature (Kelvin) lnQ = natural log of the reaction quotient Reaction quotient (Qc or Qp) - The mathematical product of the concentrations (or partial pressures) of the products of a reaction divided by the mathematical product of the concentrations (or partial pressures) reactants of a reaction AT ANY MOMENT IN TIME.
EXPLAIN THE CONCEPT OF CHEMICAL
ACTIVITY
Chemical activity is the tendency of a substance to undergo chemical changes in a system. The chemical reactivity worksheet offers an excellent database of reactivity for over 4,000 common hazardous chemicals. The database includes information about chemical reactivities towards air, water, etc. However, the reactivity may also mean chemical properties. An internet search using the key word "chemical reactivity" also gives databases for health and safety, which is hyperlinked to many sites.