1)
a) A certain organic compound is found by analysis to contain 31.9 per cent carbon and 5.30 per cent hydrogen, by weight. A qualitative test shows chlorine to be present as well. On the assumption that the only elements present are carbon, hydrogen, and chlorine, find the simplest formula of the compound.
b) By ignition with metallic sodium, the chlorine present in a 1.50-gram sample of the compound is converted to chloride ion. How many milliliters of 0.500-molar silver nitrate solution will be required for titration of the chloride ion?
c) When a 1.36-gram sample of this compound is converted to vapor, it is found to occupy 380 milliliters at 102 °C and 750 millimeters of mercury pressure. Find the molecular formula of the compound.
2) A current deposits 5.00 grams of copper from a cupric ion (Cu2+) solution in 1000 minutes.
a) What is the strength of the current in amperes?
b) How many grams of copper will the same current deposit in the same time from a cuprous ion (Cu+) solution?
c) How many liters of oxygen measured over water at 25 °C and 738 millimeters of mercury will the same current liberate in half the time?
3) The ionization constant for a certain weak acid HA is 1.0 x 10¯9. Find the following:
a) The concentration of a solution of this acid which has a pH of 5.0
b) The degree of ionization of this solution
c) The number of moles of the salt NaA which must be added to a liter of a 0.20-molar HA to produce a solution having a hydrogen ion concentration of 6.0 x 10¯10 M
4)
a) At a certain temperature, 1.00 mole of gaseous N2O4 is placed in a 1.00-liter flask, and equilibrium for the reaction N2O4(g) <===> 2 NO2(g) is attained when 4.0 per cent of the N2O4 has dissociated. Calculate the value of the equilibrium constant for the reaction.
b) At the same temperature, 0.060 mole NO2 and 0.85 mole N2O4 are placed in a 1.00-liter flask. When equilibrium is established, is there more of less than 0.060 mole NO2 present? Justify your answer.
Questions 5 - 12 not available
13) Discuss a chemical and a physical method for the determination of atomic weights. Describe the procedures used for each and compare the relative accuracies of the two methods selected.
14) Discuss the polarity of bonds and of molecules. Your discussion might include such topics as dipole moment, dielectric constant, electronegativity, and molecular geometry.
15) Discuss the measurement and significance of standard half-cell potentials (standard electrode potentials) and their applicability to the equilibrium conditions in oxidation-reduction reactions and to the prediction of the products of electrolysis.
16) Nitric acid is prepared commercially from atmospheric nitrogen. Write equations for the successive reactions involved and discuss the conditions for the industrial success of the overall process.
17) Discuss the relationships within a family of the periodic table as illustrated by the nitrogen family.
18) Describe at least three methods of separating Cu2+ and Al3+ in aqueous solution and explain the chemical principles involved in each separation. Where appropriate, summarize your descriptions by means of equations.