1. A vessel contains 142 grams of chlorine gas and 3.0 moles of argon gas at 0°C and a total pressure of 4.0 atmospheres.
(a) Calculate the volume of the flask and the partial pressure of each of the gases.
(b) When 46 grams of sodium metal is introduced into the vessel, a reaction occurs, and one of the regents is totally consumed. What weight of sodium chloride is formed?
(c) Cacluate the partial pressures of any gases present after the reaction in (b) is complete and the temperature has been brought back to 0°C. (The volumes of solid reactants and products may be ignored.)
2. The Ka for acetic acid is 1.8 x 10¯5.
(a) What volume of 0.0500-molar solution of sodium acetate should be added to 0.200 liter of 0.100-molar acetic acid in order to prepare a buffer solution with a pH of 4.50?
(b) Suppose that 0.500 liter of a buffer soultion with a pH of 4.50 is to be prepared from 0.100-molar acetic acid and 0.0500-molar sodium hydroxide. What volume of each of the two solutions would be required? (Assume that the total voume of the mixture is the sum of the volumes of the reagents used.)
3)
N2O4 <===> 2 NO2
The reaction above is carried out in a chloroform solution at 8 °C. At equilibrium, 0.100 liter of chloroform solution is found to contain 0.700 mole of N2O4 and 2.80 x 10¯4 mole of NO2 at 8 °C.
(a) Calculate the value for the equilibrium constant at 8°C.
(b) Using this constant, calculate the moles of N2O4 and NO2 which would be present at equilibrium at 8 °C when 0.100 mole of N2O4 is dissolved in enough chloroform to give 0.200 liter of solution.
Questions 4 - 12 are not available.
14.
| IONIZATION POTENTIALS, VOLTS |
IONIC RADII, ANGSTROMS |
||
| First | Second | ||
| Ra | 5.28 | 10.1 | 1.43 |
| Cs | 3.89 | 23.4 | 1.67 |
After considering the data above, comment on the fact that the oxidation potentials for each of the following half-reactions is +2.95 volts.
| Ra ---> Ra2+ + 2 e¯ |
| Cs ---> Cs+ + e¯ |
15. Consider the types of isomerism for molecules with the formula C6H12. Illustrate each of three types by structural formulas. What structural features are essential for the existence of each of these types of isomerism?
16. A student performs a titration of Fe2+ by oxidation with standard KMnO4 solution. He fails to rinse the burette with the standard solution after first rinsing it with distilled water. He then runs two successive titrations without refilling the burette. Are the determined values for iron higher or lower than the actual value? Explain why.
17. Why does the rate of a slow reaction between molecules increase more rapidly with a rise in temperature than can be accounted for by the increase in the frequency of molecular collisions?
18. Indicate the effect on the atomic number and on the mass number of the emission by an atomic nucleus of each of the following: (a) alpha particle; (b) beta particle; (c) positron; (d) neutron; (e) photon.
19. One of the evidences for the existence of ions in solutions is based on colligative properties (properties dependent on vapor pressure lowering). Describe three additional types of evidence for the existence of ions in solution.
20. Describe the field of study called chemical kinetics. In your discussion be sure to include
(a) the meanings and significance of some of the important terms;
(b) the design of experiments and the means by which they are implemented (i.e., how the necessary measurement may be made);
(c) the significance of and the reason for making kinetic studies.
21. The chemical properties of an element are determined by the electron configuration. For the elements barium, fluorine, manganese, boron, and neon, cite evidence which illustrates this statement and show how the evidence supports the statement.