Chem12 Professor Arnold
Thermodynamics Problems #3
Consider the homogeneous gas-phase reaction, 2 A + B --> C + D for which Kp is determined to be 5.56E-3 at 25°C and 1.50E-5 at 50°C.
- a. Calculate DG° for this reaction at 25°C.
- b. Calculate DG° for this reaction at 50°C.
- c. Calculate DH° for this reaction.
- d. Which way does the energy change say this reaction should go ? (to the left or to the right)
- e. Which way does the reaction go, in fact, with an increase in temperature ?
- f. Why is the reaction going in the direction it is with an increase in temperature ?
- g. Calculate DS° for this reaction.
- h. Is the sign of DS°consistent with the balanced chemical equation ?
- i. Calculate Kp for this reaction at 0°C.
- j. Sketch a graph of ln K versus 1/T for this reaction.
- k. Calculate the temperature at which DG° is equal to zero.
- l. True or False: This reaction has both an energy change and an entropy change which are favorable for spontaneity.
Dr. Merle Arnold | Physical Science Department | Santa Monica College | last updated 8/12/01