Chem 130 Chp. 15

Chp. 15 Chemical proportionality Occurs when a chemical re implement and its reverse reception (opposing reactions) proceed at the same put At offset the rate at which products are produced from reactants equals the rate at which reactants are produced from products At residuum a particular ratio of tautness terms equals a changeless The radical of an equilibrium mixture does not flip with time Kc equilibrium constant 15. 2 Law of mass action expresses the relationship between the meannesss of the reactants and products present at equilibrium 5. 3 * * LARGE respect OF Kc equaliser mixture contains more than products than reactants = product side (right side) K > 1 *SMALL VALUE OF Kc Equilibrium mixture contains less products than reactants = reactant side (left side) K < 1 The equilibrium-constant expression for a reaction indite in one centering is the reciprocal of the one for the reaction written in the reverse direction Multiplying exclusively the stoichiom etric coefficients by a get along gives the equilibrium constant for the original reaction raised to that government issue 15. 4Concentrations of PURE SOLIDS and LIQUIDS DO NOT appear in equilibrium expression L S 15. 5 ICE TABLS 15. 6 15. 7 Le chateliers principle IF a system at equilibrium is disturbed by a change in temperature, twitch, or the concentration of one of the components, the system will put forward its equilibrium position so as to counteract the effect of the disturbance % of NH3 at equilibrium decreases with increasing temperature and increases with increasing pressure * * Endothermic reaction increase in temperature shifts equilibrium to right reactant bsorbs high temperature increase T results in an increase K * Exothermic reaction Temperature increase shifts equilibrium to left product gives off heat Increasing T results in fall K * * Increasing pressure ( decrease volume) equilibrium shifts in the direction producing the smaller number of moles of gas wil l constrict the pressure * * Decreasing pressure (increasing volume) equilibrium shifts in the direction producing the larger number of moles of gas produces more pressure