Chem. 152 – Chapter 13 Reading Objectives – Zumdahl

 

1.       Understand the meanings of the term chemical equilibrium.  Understand what it means to say that a reaction lies to the right or to the left. 

 

2.       Be aware that chemical equilibria are dynamic situations expressed as reversible reactions.

 

3.       Know the format for how equilibrium constants (K) are calculated.  Understand how coefficients from the equation are included in this calculation.  Be able to calculate equilibrium constants.  Understand that, for our purposes, equilibrium constants are unitless.

 

4.       Know whether temperature and initial reactant concentrations affect the value of K.

 

5.       Understand the meaning of the value of K, particularly when K >> 1 and when K << 1.  Be aware that the individual reactant and product concentrations can vary at equilibrium, but the value of K cannot.

 

6.       Understand how the following changes in the format in which an equilibrium equation is written influence the calculation of Kc: switching reactants and products, multiplying the coefficients by a constant.

 

7.       Be able to solve equilibrium problems using partial pressures of gases.

 

8.       Understand the relationship between Kp and K.  Be able to use this relationship to covert between K and Kp.

 

9.       Know what the terms heterogeneous equilibrium and homogeneous equilibrium mean.

 

10.   Understand how pure solids and pure liquids are dealt with in equilibrium constant calculations.  Be able to perform calculations dealing with heterogeneous equilibria.

 

11.   Be able to calculate reaction quotients (Q) and use them to predict where a reaction system lies with respect to equilibrium and how the system must shift in order to reach equilibrium.

 

12.   Be able to calculate equilibrium concentrations or pressures from an equilibrium constant.  Note: you may need to use the quadratic formula.

 

13.   Be familiar with and understand the significance of LeChatelier’s Principle.

 

14.   Be able to qualitatively describe the effects of changes in concentration, changes in pressure or volume, and changes in temperature on the position of an equilibrium (shift to left or shift to right) and its equilibrium constant.  Know how values of Q and K are affected in each case.  For temperature changes, be able to differentiate between effects on exothermic and endothermic reactions.

 

15.   Be able to perform calculations to find Kc or equilibrium concentrations following application of stress to an equilibrium situation.

 

From chapter 16, section 8:

16.   Be able to perform calculations which relate the standard free energy change to the equilibrium constant.  Understand what relationship must exist between the values of DGorxn and K.