Part 1: Types of Chemical Bonds

Transcription

1 Unit 7: Bonding Review Directions: Complete as much of this packet as you can WITHOUT USING YOUR NOTES. Treat it as a practice test. Star any questions that you cannot answer on your own, and then go back and use your notes to complete these questions. Only then should you compare your answers to the key on my website. Part 1: Types of Chemical Bonds 1) List the three types of chemical bonds in order from weakest to strongest. 2) Determine what type of bonds will be found in each of the following substances. a) Salt (NaCl) e) Potassium Iodide b) Bronze c) Diamond d) Water f) Methane g) Copper wire h) Calcium carbonate 3) Explain how you determine the relative bond strengths of ionic compounds. Your answer should include a scientific law (mathematical equation). (complete sentences) 4) Rank each set of ionic compounds from lowest to highest lattice energy (bond strengths). a) BeO, BaO, CaO, SrO b) KCl, AlBr3, MgI2 c) Mg3N2, NaF, K2Se, AlCl3, SrS, GaP d) KBr, MgCl2, CsI, Na2S, Na3P, AlCl3 5) Explain the difference between the two types of covalent bonds. (complete sentences) 6) Explain how you determine the relative bond strengths of covalent compounds. (complete sentences)

2 7) Circle the stronger bond in each of the following pairs and give a reason for your choice. a) C-C or C=C b) C-N or C N c) C O or C=O d) H-F or H-Cl e) C-H or O-H f) C-N or C-O Part 2: Lewis Dot Structures & VSEPR 8) What rule governs the construction of Lewis dot structures? What two elements are the exception to this rule and why? 9) What theory explains the 3D shapes of molecules? What does this acronym stand for? Why do the electron domains in a molecule arrange themselves according to this theory? 10) Draw the Lewis dot structure for each molecule given below and use it to determine the shape and bond angles of the molecule. Then determine the polarity for each bond and draw dipole arrows if necessary. Finally, state the polarity of each molecule. a) Methane c) Ammonium b) Ammonia d) Water

3 e) Sulfur Dibromide i) Cyanide Name: f) Hydrochloric Acid j) Hydroxide g) Phosphorus Trichloride k) Formaldehyde (COH2) h) Boron Trifluoride l) Dichloromethane (CH2Cl2)

4 m) Fluoromethane (CH3F) n) Hypochlorite Part 3: Intermolecular Forces 11) What is an intermolecular force? How does it compare to an intramolecular force? (complete sentences) 12) List the four types of intermolecular forces in order from weakest to strongest. 13) Define each type of intermolecular force, and explain what types of molecules exhibit each type of intermolecular force. (complete sentences) 14) Explain how boiling point is related to the strength of intermolecular forces in a substance. (complete sentences)

5 15) Which compounds from question 10 are capable of dipole-dipole interactions? Explain why. (complete sentences) 16) Circle the compound(s) below that are capable of hydrogen bonding. CH3OCH3 CH3COCH3 CH3CH2OH H2CO CH3F 17) Based on their given boiling points, rank the following compounds from least polar to most polar. Propane (231 K) Dimethyl Ether (248 K) Acetonitrile (355 K) Methyl Chloride (249 K) Butane (135 K) 18) Circle all of the pictures below that show hydrogen bonds. 19) Rank each set of compounds from lowest to highest boiling point. a) LiCl, C3H7OH, C4H8, N2 b) Cl2, I2, Br2 c) CH3CH2CH2OH, Ca(OH)2, CH3CH2CH2CH3, CH3CH2OCH3 d) CH3CH2CH2NH2, LiCl, N(CH3)3, CH3CH2CH2CH2NH2 20) Rank each set of compounds in the order in which they will evaporate. a) CH3CH2CH2CH2CH2OH, CH3CH2CH2OH, CH3CH2CH2CH3, CH3CH2OCH2 b) C4H9OH, C2H5OH, C4H10, CaBr2 c) CH3CH2OCH2CH3, CH3CH2OCH3, CH3CH2CH2CH3, CH3CH2CH2CH2NH

6 21) Hexane, C6H14 (MW = 86) has a boiling point of 68 o C. Ethanol, CH3CH2OH (MW = 46) has a boiling point of 78 o C. Mark each statement as true (T) or false (F). a) Ethanol must have stronger intermolecular attraction, based on its higher boiling point. b) Ethanol has a higher boiling point because of greater London dispersion forces c) Both hexane and ethanol have hydrogen bonding d) Ethanol has a higher boiling point due to hydrogen bonding e) Hydrogen bonding and London dispersion forces are competing here (one favors hexane and one favors ethanol). In this case, the hydrogen bonding evidently wins.