Department
of Earth Science |
Northeastern
Illinois University
AQUEOUS
GEOCHEMISTRY
ESCI 406
Spring, 2005
Daily
Objectives
#11 (February 21,
2005)
Dr. Sanders
Quiz #3 will be today in the final 30 minutes of class.
Review
v Write the equation that shows the relationship between DGR and DGRo, and explain the relationship in your own words.
v Under what conditions would DGR and DGRo for a chemical reaction be equal to each other? Under what conditions would they be different from each other?
By the end of today's class, you should be able to do the following:
v On the table at the front of the room are two beakers, each holding a liter of water. Let's dissolve a mole of NaCl into one beaker, and a half-mole into the other. Assume STP conditions. For each beaker, calculate the DGR for the reaction NaCl(s) = Na+(aq) + Cl-(aq)
v Explain: Is the system in the first beaker at equilibrium with respect to this reaction? How about the second beaker? If you decide either system is not in equilibrium, explain what it would take to bring it to equilibrium.
v Define concentration of an aqueous species, and tell how it differs from "activity" (also called "effective concentration") .
v Define and give the formula for the calculation of equilibrium constant (Keq) of the reaction aA + bB = cC + dD
v Distinguish between equilibrium constant (Keq) and solubility product constant (Ksp).
v Use DGRo data to calculate equilibrium constant (Keq) of a reaction for a system that is at equilibrium (hint: what does that tell you about the DGR?) 25oC, and 1 atm pressure.
v Write and use the "shortcut" formula that relates DGR to Keq for a system at equilibrium and STP.
Quiz #3 will be today in the final 30 minutes of class.
Review
v Write the equation that shows the relationship between DGR and DGRo, and explain the relationship in your own words.
v Under what conditions would DGR and DGRo for a chemical reaction be equal to each other? Under what conditions would they be different from each other?
By the end of today's class, you should be able to do the following:
v On the table at the front of the room are two beakers, each holding a liter of water. Let's dissolve a mole of NaCl into one beaker, and a half-mole into the other. Assume STP conditions. For each beaker, calculate the DGR for the reaction NaCl(s) = Na+(aq) + Cl-(aq)
v Explain: Is the system in the first beaker at equilibrium with respect to this reaction? How about the second beaker? If you decide either system is not in equilibrium, explain what it would take to bring it to equilibrium.
v Define concentration of an aqueous species, and tell how it differs from "activity" (also called "effective concentration") .
v Define and give the formula for the calculation of equilibrium constant (Keq) of the reaction aA + bB = cC + dD
v Distinguish between equilibrium constant (Keq) and solubility product constant (Ksp).
v Use DGRo data to calculate equilibrium constant (Keq) of a reaction for a system that is at equilibrium (hint: what does that tell you about the DGR?) 25oC, and 1 atm pressure.
v Write and use the "shortcut" formula that relates DGR to Keq for a system at equilibrium and STP.