Due: Date of Semester 1 Final Exam
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AP CHEMISTRY REVIEW PROJECT, SEMESTER 1
1. A mixture of H2(g), O2(g), and 2 milliliters of H2O(l) is present in 0.500-liter rigid container
at 25 °C. The number of moles of H2 and the number of moles of O2 are equal. The total
pressure is 1,146 millimeters of mercury. (The equilibrium vapor pressure of pure water is 24
millimeters mercury.)The mixture is sparked, and H2 and O2 react until one reactant is
completely consumed.
a. Identify the reactant remaining and calculate the number of moles of the reactant
remaining.
b. Calculate the total pressure in the container at the conclusion of the reaction if the
final temperature is 90 °C.
c. Calculate the number of moles of water present as vapor in the container at 90 °C.
2. Use simple structure and bonding models to account for each of the following.
a. The bond length between the two carbon atoms is shorter in C2H4 than in C2H6.
b. The H - N - H bond angle is 107.5° in NH3.
c. The bond lengths in SO3 are all identical and are shorter than a sulfur-oxygen
single bond.
d. The I3¯ ion is linear.
3. The diagram shows the first ionization energies for the elements from Li to Ne. Briefly (in
one to three sentences) explain each of the following in terms of atomic structure.
a. In general, there is an increase in the first ionization energy from Li to Ne.
b. The first ionization energy of B is lower than that of Be.
c. The first ionization energy of O is lower than that of N.
d. Predict how the first ionization energy of Na compares to those of Li and of Ne.
Explain.
4. An experiment is performed to determine the empirical formula of a copper iodide formed by
direct combination of elements. A clean strip of copper metal is weighed accurately. It is
suspended in a test tube containing iodine vapor generated by heating solid iodine, A white
compound forms on the strip of copper, coating it uniformly. The strip with the adhering
compound is weighed. Finally, the compound is washed completely from the surface of the
metal and the clean strip is dried and reweighed.
DATA TABLE
Mass of clean copper strip
1.2789 grams
Mass of copper strip and compound 1.2874 grams
Due: Date of Semester 1 Final Exam
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Mass of copper strip after washing 1.2748 grams
a. State how you would use the data above to determine each of the following.
(Calculations not required.)
i. The number of moles of iodine that reacted
ii. The number of moles of copper that reacted
b. Explain how you would determine the empirical formula for the copper iodide.
c. Explain how each of the following would affect the empirical formula that could
be calculated.
i. Some unreacted iodine condensed on the strip.
ii. A small amount of the white compound flaked off before weighing.
5. The molecular formula of a hydrocarbon is to be determined by analyzing its combustion
products and investigating its colligative properties. The hydrocarbon burns completely,
producing 7.2 grams of water and 7.2 liters of CO2 at standard conditions.
a. Calculate the mass in grams of O2 required for the complete combustion of the
sample of the hydrocarbon.
b. The hydrocarbon dissolves readily in CHCl3. The freezing point of a solution
prepared by mixing 100. grams of CHCl3 and 0.600 gram of the hydrocarbon is 64.0 °C. The molal freezing-point depression constant of CHCl3 is 4.68 °C / molal
and its normal freezing point is -63.5 °C. Calculate the molecular weight of the
hydrocarbon.
c. What is the molecular formula of the hydrocarbon?
6. An experiment is to be performed to determine the molecular mass of a volatile liquid by the
vapor density method. The equipment shown above is to be used for the experiment. A
barometer is also available.
a. What data are needed to calculate the molecular mass of the liquid?
Due: Date of Semester 1 Final Exam
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b. What procedures are needed to obtain these data?
c. List the calculations necessary to determine the molecular mass.
d. If the volatile liquid contains nonvolatile impurities, how would the calculated
value of the molecular mass be affected? Explain your reasoning.
7. Experimental data provide the basis for interpreting differences in properties of substances.
Account for the differences in properties given in Tables 1 and 2 above in terms of the
differences in structure and bonding in each of the following pairs.
a. MgCl2 and SiCl4
b. MgCl2 and MgF2
c. F2 and Br2
d. F2 and N2
8. Explain each of the following in terms of atomic and molecular structures and/or
intermolecular forces.
a. Solid K conducts an electric current, whereas solid KNO3 does not.
b. SbCl3 has a measurable dipole moment, whereas SbCl5 does not.
c. The normal boiling point of CCl4 is 77 °C, whereas that of CBr4 is 190 °C.
d. NaI(s) is very soluble in water whereas I2(s) has a solubility of only 0.03 gram per
100 grams of water.
NO2 NO2¯ NO2+
9. Nitrogen is the central atom in each of the species given above.
a. Draw the Lewis electron-dot structure for each of the three species.
b. List the species in order of increasing bond angle. Justify your answer.
c. Select one of the species and give the hybridization of the nitrogen atom in it.
d. Identify the only one of the species that dimerizes and explain what causes it to do
so.
10. Give the formulas to show the reactants and the products for ALL of the following chemical
reactions. Each of the reactions occurs in aqueous solution unless otherwise indicated.
Represent substances in solution as ions if the substance is extensively ionized. Omit
formulas for any ions or molecules that are unchanged by the reaction. In all cases a reaction
occurs. You need not balance.
Example: A strip of magnesium is added to a solution of silver nitrate.
Mg + Ag+ ---> Mg2+ + Ag
a. Solutions of sodium iodide and lead nitrate are mixed.
b. A solution of ammonia is added to a solution of ferric chloride.
c. A solution of hydrogen peroxide is heated.
d. Solutions of silver nitrate and sodium chromate are mixed.
e. Hydrogen sulfide gas is bubbled through a solution of potassium hydroxide.
f. Solid dinitrogen pentoxide is added to water.
g. A piece of solid bismuth is heated
Due: Date of Semester 1 Final Exam
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h. A strip of copper metal is added to a concentrated solution of sulfuric acid.