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Chapter 9
Chemical Bonds
9.CO
Title
 Cubic crystals of table salt
Caption
 Cubic crystals of sodium chloride, table salt are shown.
Keywords
 salt, lattice, bonding, crystal
9.1ab
Title
 Electrostatic attractions & repulsions in 2 simple molecular species
Caption
 The electrostatic attractions (red) and repulsions (blue) in and H2 are described in the text.
Keywords
 bonding, electrostatics
9.2
Title
 Energy of interaction of 2 hydrogen atoms
Caption
 The molecular models and graph together show that the lowest energy for two H atoms comes at the internuclear distance in the H2 molecule, 74 pm.
Keywords
 internuclear distance, bonding, van der waals, energy, graph
9.4
Title
 formation of a crystal of sodium chloride
Caption
 Formation of a crystal of sodium chloride requires ionization of sodium and formation of chloride ions from chlorine.
Keywords
 salt, crystal, lattice, empirical formula, ionic bonding, bonding
9.5
Title
 Born-Haber cycle for 1 mol of sodium chloride
Caption
 The starting point and the five steps of the cycle are shown. (DH values are not to scale.) The sum of the five enthalpy changes (DH1 to DH5) gives DH¡f. The equivalent one-step reaction for the formation of NaCl(s) directly from Na(s) and 1/2 Cl2(g) is shown in red.
Keywords
 hess' law, born haber cycle, lattice energy, salt, enthalpy, ionizaition energy, graph, state function
9.6
Title
 Four hydrogen compounds of 2nd period nonmetals
Caption
 The formulas of the four molecules can be deduced from Lewis structures, but their geometrical shapes cannot. Geometric shapes of molecules can be predicted by methods presented in Chapter 10, and they can be precisely established by experiment.
Keywords
 compounds, Lewis structure, periodic trends, molecular formula
9.7
Title
 Paramagnetism of oxygen
Caption
 Liquid oxygen is held by a magnet. This property is paramagnetism.
Keywords
 paramagnetism, oxygen, lewis structure, electron, magnet, electron configuration
9.7.3
Title
 Electronegativity
Caption
 In the periodic table, the trend in electronegativity for elements is an increase toward the right. Electronegativities are also highest at the "top" of a group. The most electronegative element is Fluorine; the least electronegative is Francium.
Keywords
 electronegativity, periodic trends, periodic table
9.8
Title
 Pauling's electronegativities of the elements
Caption
 Electronegativity values vary from a low of 0.7 from Francium and Cesium to a high of 4.0 for Fluorine. Because noble-gas compounds are limited to just a few compounds of Kr and Xe, electronegativities for the Group 8A elements are not included.
Keywords
 electronegativity, periodic table, bonding, electron affinity, periodic trends
9.9
Title
 Electronegativities in relation to the periodic table
Caption
 In general, electronegativities increase in the directions of the colored arrows. l
Keywords
 periodic trends, electronegativity, periodic table
9.10
Title
 Electronegativity & bond type
Caption
 Bonding between atoms is a continuum from ionic to covalent. The larger the difference in electronegativity between two bonded elements, the more ionic in character that the bond becomes.
Keywords
 bonding, ionic bonding, covalent bonding, polar covalent bonding.
9.11
Title
 Nonpolar & polar covalent bonds
Caption
 In the H2 molecule, there is an even distribution of electron charge density between the atoms. In the HCl molecule, electron charge density is displaced toward the Cl atom.
Keywords
 polar covalent bonding, covalent bonding, bonding, electronegativity
9.11.1
Title
 Designations in polar covalent bonds.
Caption
 Greek letter delta (d) is used to indicate the polar nature of the bond.
Keywords
 polar covalent bonding, paritally negative, partially positive, bonding,
9.11.2
Title
 Diagram of a polar covalent bond
Caption
 A cross-based arrow is used to indicate the polar nature of the bond.
Keywords
 polar covalent bonding, paritally negative, partially positive, bonding,
9.11.4
Title
 Structure of ethane
Caption
 Hydrogenm atoms are terminal atoms in molecules.
Keywords
 hydrogen, Lewis structure, bonding
9.11.5
Title
 Lewis structure of COCl2
Caption
 The central atom of a structure usually has the lowest electronegativity. In this case, the electronegativity of carbon is lowest of the elements in this molecule. Therefore, the other elements are drawn as bonded to the carbon.
Keywords
 bonding, electronegativity, Lewis structures
9.11.6a
Title
 Lewis structure of Chloric acid (HOClO2)
Caption
 In oxoacids, hydrogen atoms are usually bonded to oxygen atoms.
Keywords
 bonding, Lewis structures, oxoacids
9.11.6b
Title
 Lewis structure of Sulfuric acid [(HO)2SO2]
Caption
 In oxoacids, hydrogen atoms are usually bonded to oxygen atoms.
Keywords
 obnding, lewis structures, oxoacids
9.11.7a
Title
 Lewis structure of Sulfuryl fluoride (SO2F2)
Caption
 Molecules and polyatomic acids usually have compact, symmetrical structures. Shown is SO2F2, which is has a symmetrical, spherical structure (left) not a linear one (right.)
Keywords
 Lewis structures, bonding
9.12
Title
 Concept of formal charge illustrated
Caption
 Lewis structure (a) is more plausible than (b) because it has no formal charges vs. formal charges of +2, +2 and 0 for the atoms in the molecule.
Keywords
 formal charge, lewis structures
9.12.13
Title
 Central boron atom & 3 fluorine atoms
Caption
 Boron in this Lewis structure does not have a complete octet. We most often see incomplete octets in Be, B, and Al.
Keywords
 octet rule, lewis structures
9.12.14
Title
 Possible Lewis structure for BF3
Caption
 Boron-to-flourine double bond structure is one possible Lewis structure for BF3. It does ensure that each atom has a complete octet. However, the formal charges are not favorable. This is not an accurate representation of the structure of BF3.
Keywords
 octet rule, Lewis structure
9.12.15
Title
 Resonance structures of BF3
Caption
 A hybrid of 4 resonance structures is the best Lewis representation of the "real" structure of a BF3 molecule.
Keywords
 octet rule, resonance, lewis structures
9.12.16
Title
 A coordinate covalent bond formed by a flouride ion
Caption
 When both of the electrons in a bond are supplied by one of the atoms, a coordinate covalent bond is formed.
Keywords
 lewis structure, bonding, coordinate covalent bond
9.12.17a
Title
 Phosphorus pentachloride structure
Caption
 Phosphorus violates the octet rule in this structure by having 5 bonds.
Keywords
 octet rule, lewis structures, bonding, valence
9.12.17b
Title
 Sulfur hexaflouride structure
Caption
 Sulfur violates the octet rule in this structure by having 5 bonds.
Keywords
 octet rule, lewis structures, bonding, valence
9.12.19
Title
 Possible Lewis structure for perchlorate ion, pt. 1
Caption
 In this Lewis structure for perchlorate ion, all atoms follow the octet rule but there is a positive formal charge on chlorine along with charges on each of the oxygen atoms. This suggests that this structure for perchlorate ion is not favorable.
Keywords
 octet rule, Lewis structure, bonding, formal charge
9.12.20
Title
 Possible Lewis structure for perchlorate ion, pt. 2
Caption
 Although chlorine violates the octet rule in this Lewis structure, experimental evidence suggests that this structure possibly contributes to the hybrid structure.
Keywords
 lewis structure, bonding, octet rule, formal charge
9.12.21A
Title
 Possible Lewis structure for perchlorate ion, pt. 3
Caption
 Experimental evidence suggests that this ionic structure possibly contributes to the hybrid structure of the perchlorate ion.
Keywords
 bonding, lewis structure, resonance, hybrid structure, octet rule
9.13
Title
 Some bond dissociation energies compared
Caption
 The same quantity of energy (436 kJ/mol) is required to break all H2 bonds. In water, more energy is required to break the first H-O bond (499 kJ/mol) than to break the second (428 kJ/mol). The value of the H-O bond energy in Table 9.1 is an average value based on water and other compounds that contain the H-O bond.
Keywords
 Bond energy, bond dissociation energy, enthalpy
9.14
Title
Caption
 The values shown, in kilojoules per mole, are the amounts of energy absorbed in breaking bonds in the reactants, N2 and H2, and released in forming bonds in the product, N2H4.
Keywords
 enthalpy, bond dissociation energy, bonding, enthalpy of formation
9.16.4Box
Title
 Bromine molecules reacts w/unsaturated fats
Caption
 The reddish brown color of bromine vapor (left) is removed when a strip of uncooked bacon is a placed in the beaker (right). Bromine molecules react with unsaturated fats in the bacon in a reaction similar to a hydrogenation reaction.
Keywords
 hydrogenation, bonding, bromination, saturated fats, unsaturated fats.
9.16.5Box
Title
 Corn oil and hydrogenation products
Caption
 The unsaturated fats in oils, such as corn oil shown here, can be partially hudrogenated to form more saturated fats. Saturated fats are solids at room temperature. Corn oil margerine (a solid) is made from hydrogenated corn oil.
Keywords
 saturated fats, unsaturated fats, bonding,
9.15
Title
 Molecular model of ethene
Caption
 Ethene, C2H4, contains 4 C-H bonds and a C=C double bond. The molecule is planar.
Keywords
 spacefill model, bonding, alkene, double bond
9.16
Title
 Molecular model of ethyne
Caption
 Ethyne, C2H2, contains one C-C triple bond and 2 C-H bonds. The molecule is linear in structure.
Keywords
9.17
Title
 The formation of polyethylene
Caption
 In the synthesis of polyethylene, many monomer units join together to form giant polymer molecules. In this computer-generated representation, the yellow dots indicate a new bond forming as an ethylene molecule (upper right) is added to the growing polymer chain.
Keywords
 polymer chemistry, polyethylene, addition reactions
9.17.1
Title
 Production of plastic products
Caption
 A giant bubble of a tough, transparent plastic film emerges from the die of an extruding machine. The film is used in packaging, consumer products, and food-service operations.
Keywords
 polymer chemistry, plastic
9.17.2
Title
 Amino acid polymerization
Caption
 Two amino acid molecules join by eliminating a molecule of water between them and forming a peptide bond.
Keywords
 amino acid, protein, polypeptide, bonding, polymerization, dehydration.
9.17.3
Title
 Formation of a polypeptide
Caption
 More amino acids can be added to the chain, until a long chain forms.
Keywords
 amino acid, protein, polypeptide, bonding, polymerization
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