pre -TEST Big Idea 2 Chapters 8, 9, 10

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1 Name: AP Chemistry Period: Date: R.F. Mandes, PhD, NBCT Complete each table with the appropriate information. Compound IMF Compound IMF 1 NiCl 3 7 ClCH 2 (CH 2 ) 3 CH 3 2 Fe 8 H 2 CF 2 3 Ar 9 H 2 NCH 2 CH 3 COOH 4 SiO 2 10 CH 3 OH 5 CH 3 CH 2 NH 2 11 C (graph) 6 CH 3 OCH 3 12 N 2 Compounds IMF(s) for each Rank IMF (weaker / stronger) Rank Melting/Boiling Pt. (lower / higher) 13 CH 3 CH 2 CH 3 CH 3 CH 2 CH 2 CH 3 14 CH 3 C(O)CH 3 CH 3 CH 2 OH 15 H 2 NCH 2 CH 2 CH 3 H 2 NCH 3 CH 2 NH a. How much energy is needed to convert 10.0 g of ice at 5.0 C to liquid water at 40.0 C? Specific heat of ice is 2.03 J/(g. C), liquid water is J/(g. C), heat of fusion kj/g, heat of vaporization is 2.25 kj/g b. Sally has a cup of 66 C coffee that is just too hot to drink. Sally will only drink coffee that is at or below 43 C. Sally adds 20.0 g of ice to her coffee. Will she be able to drink it?

2 Complete the Table With the Appropriate Information Molecular Formula Lewis Structure Geometry and Hybridization of the central atom Bonds: Polar or Nonpolar Molecule: Polar or Nonpolar CCl 4 NF 3 OF 2 BF 3 C 2 H 2 BeF 2 TeF 4

3 2014 Nonmetal C N O Ne Si P S Ar Formula of Compound CF 4 NF 3 OF 2 No SiF 4 PF 3 SF 2 No 1. Some binary s that form between fluorine and various nonmetals are listed in the table above. A student examines the data in the table and poses the following hypothesis: the number of F atoms that will bond to a nonmetal is always equal to 8 minus the number of valence electrons in the nonmetal atom. (a) Based on the student s hypothesis, what should be the formula of the that forms between chlorine and fluorine? (b) In an attempt to verify the hypothesis, the student researches the fluoride s of the other halogens and finds the formula ClF 3. In the box below, draw a complete Lewis electron-dot diagram for a molecule of ClF 3. (c) Two possible geometric shapes for the ClF 3 molecule are trigonal planar and T-shaped. The student does some research and learns that the molecule has a dipole moment. Which of the two shapes is consistent with the fact that the ClF 3 molecule has a dipole moment? Justify your answer in terms of bond polarity and molecular structure. In an attempt to resolve the existence of the ClF 3 molecule with the hypothesis stated above, the student researches the s that form between halogens and fluorine, and assembles the following list. Halogen Formula(s) F F 2 Cl Br BrF, BrF 3, BrF 5 I IF, IF 3, IF 5, IF 7 (d) Based on concepts of atomic structure and periodicity, propose a modification to the student s previous hypothesis to account for the s that form between halogens and fluorine.

4 2013 Answer the following questions using principles of molecular structure and intermolecular forces. Compound Empirical Formula Solubility in Water Boiling Point ( qc) 1 C 2 H 6 O Slightly soluble 24 2 C 2 H 6 O Soluble 78 Compounds 1 and 2 in the data table above have the same empirical formula, but they have different physical properties. (a) The skeletal structure for one of the two s is shown below in Box X. (i) Complete the Lewis electron-dot diagram of the molecule in Box X. Include any lone (nonbonding) pairs of electrons. Box X Box Y (ii) In Box Y above, draw the complete Lewis electron-dot diagram for the other, which is a structural isomer of the represented in Box X. Include any lone (nonbonding) pairs of electrons. (b) On the basis of the complete Lewis electron-dot diagrams you drew in part (a) and the information in the data table above, identify which, 1 or 2, has the structure represented in Box X. Justify your answer in terms of the intermolecular forces present in each.

5 Pre Test Big Idea 2 {chap 8,9,10} Use the information in the following table to answer parts (c) and (d). Name Lewis Electron-Dot Diagram Boiling Point (qc) Vapor Pressure at 20qC (mm Hg) Dichloromethane Carbon tetrachloride (c) Dichloromethane has a greater solubility in water than carbon tetrachloride has. Account for this observation in terms of the intermolecular forces between each of the solutes and water. (d) In terms of intermolecular forces, explain why dichloromethane has a higher vapor pressure than carbon tetrachloride. (e) The complete Lewis electron-dot diagram of methanal (formaldehyde) is shown in the box below. Molecules of methanal can form hydrogen bonds with water. In the box below, draw a water molecule in a correct orientation to illustrate a hydrogen bond between a molecule of water and the molecule of methanal. Use a dashed line to represent the hydrogen bond.