CHEM 113 1st Edition Lecture 12 Outline of Last Lecture I. How to represent K and QOutline of Current Lecture - K and Q for heterogeneous equilibrium- Expressing equilibria with pressure terms- Determining the direction of a reaction.Current Lecture- K and Q for heterogeneous equilibriumo A heterogeneous equilibrium involves reactants and/or products in different phaseso A pure solid or liquid always has the same concentration, or the same number of moles per liter of solid or liquid.o The expressions for Q and K include only species whose concentrations change asthe reaction approaches equilibrium. Therefore, pure solids and liquids are omitted from the expression for Q and K - Expressing equilibria with pressure termso K for a reaction may be expressed using partial pressures of gaseous reactants instead of molarity. This is used because gas pressure because it is easier to measure. The following is the equation for k expressed as partial pressure and can be derived from the ideal gas law If the amount (mol) of gas does not change in the reaction, then K of partial pressure equals K of concentration.These notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.- Determining the direction of reactionoo The value of q indicated the direction in which a reaction must proceed to reach equilibrium If Q< K the reactants must increase and the products decrease If Q> K the reactants must decrease and the products increase If Q=K, the system is at equilibrium and no further net change takes
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