Exam 3 Review Sheet for CHM3910: Fall 2005 - Topics and Instructions, Exams of Chemistry

Download Exam 3 Review Sheet for CHM3910: Fall 2005 - Topics and Instructions and more Exams Chemistry in PDF only on Docsity! CHM3910 Fall 2005 Review Sheet for Exam 3 Exam 3 will cover sections 6.1 – 6.4, 6.8 and 7.8 – 9.4 of LMS. You will be provided with the Equation Sheet for Exam 1, relevant physical constants, a periodic table (if needed), and a list of standard reduction potentials. In addition, you may bring a 3” × 5” index card with whatever information you wish hand written on both sides. You should expect the exam to take about 2 hours and you will need a scientific calculator. There will be a mixture of long answer questions and shorter questions such as multiple choice and true/false. Below is a list of topics for review; however, this is just a guide for studying. Anything that was discussed in class or in the textbook could be on the exam. Pay special attention to homework assignments, in class examples, and the end of chapter problems. Understand what osmosis and osmotic pressure are. Know and be able to use van’t Hoff’s equation for osmotic pressure. Know the definitions of components, phases, constituents and degrees of freedom as they apply to chemical systems. Be able to calculate the number of degrees of freedom in a system using the Gibbs phase rule. Be able to identify the different regions and lines on a single component phase diagram. Know what allotropes are. Be able to identify the different regions of a pressure-composition or temperature-composition phase diagram for a two component system with both liquid and vapor present. Be able to use Raoult’s Law to calculate the mole fraction of each component in the liquid phase (X) in a two- component, two-phase system. Be able to calculate the mole fraction of each component in the gas phase (Y) in the same system by using the Law of Partial Pressures/Dalton’s Law. Know what a tie line is and know how it can be used along with the lever rule to determine the compositions of the liquid and vapor phases for a given overall mole fraction. Know what an azeotrope is and be able to identify the azeotropic composition on a phase diagram. Know how the process of distillation can be related to a two-component, two-phase diagram. Know how azeotropes affect the process of distillation. Be able to identify positive and negative deviations from Raoult’s Law on two-component, two-phase diagrams. Be able to interpret the different components present and their phases based on a two-component, multi-phase diagram (Fig. 6.11, 6.12, or 6.16, for example). Know the definition of a eutectic point and be able to identify one on a phase diagram. Understand what is plotted along each side of the triangle and what each corner corresponds to in a ternary (three- component, one-phase) diagram. You will only be expected to know the basics about these and you will not have to interpret a real one. Be able to calculate thermodynamic properties (∆H, ∆S, ∆G) for reactions involving ions by using tabulated values. Know that the enthalpy and entropy of formation and the standard molar entropy for an aqueous H+ ion are all zero by definition. Know that the standard values for hydration of a gas phase hydrogen ion are also defined to be zero. Know the basic premise of the Born model for estimating ∆hydG° for an ion in solution. Know the equations for ∆G° and ∆S° of hydration based on this model, and know under what circumstances the model works best. Have a qualitative picture of how water interacts with ions in solution. Understand how the number of solvating water molecules depends on the size of the ion, and how the amount of structure within the liquid water varies as you get farther from the solvated ion. Know the difference between an oxonium ion and a hydronium ion. Understand why electrolyte solutions behave much less ideally than nonelectrolyte solutions, and understand that because of this the use of activities instead of molalities or concentrations is particularly important for solutions of electrolytes. Know that to change from a molality to an activity the molality should be replaced by the molality times the activity coefficient (ai = miγi). Know the basic assumption of the Debye-Hückel theory of ions in solution and be able to calculate the mean ionic activity coefficient for a solution by using the Debye-Hückel Limiting Law. Know that for water the constant B in the D-H equation is equal to 0.509. Know the definition of the mean ionic activity coefficient and know why individual activity coefficients for the cations and anions in a solution cannot be calculated. Be able to calculate the ionic strength of a solution. Know under what conditions the Debye-Hückel Limiting Law works best. We skipped sections 7.11 – 7.13. Be able to identify the parts of an electrochemical cell. Know which sides the anode and cathode are on and whether oxidation or reduction occurs at each electrode. Know which direction the cations and anions flow within the salt bridge and know which direction corresponds to the spontaneous flow of electrons.