MOOREHW1 - lESL-:apter 1: The Katine of Chemistry 45....

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Unformatted text preview: lESL-:apter 1: The Katine of Chemistry 45. Answer: macroscopic world; a pal'allelpiped shape; the atom crystal arrangement is parallel piped shape. .S‘n'oregr and Eripfqmrfoii: The crystal of halite pictured is in the macroscopic world. Its shape is cubic or parallelepiped. It could be expected that the arrangement of particles (atoms and-"or ions] in the nanoscale world are also arranged in a cubic or parallelepiped fashion. 'Jl |u . A:351icits-Espimrcmon .' The melting point is the temperature at which a solid changes into a liquid. In the nanoscale picture. the liquid molecules are moving faster and they are farther apart. That motion spreads out the molecules and makes the volume larger. even though the collection of molecules have the same mass. Hence. the density of the liquid is smaller than the density of the solid. The boiling point is the temperature at which the liquid molecules change into gas-phase molecules. In the nanoscale picture. the gas molecules are moving faster and they are farther apart. That motion spreads out the molecules and makes the vohime larger. even though the collection of molecules have the same Inass. Hence. the density of the gas is smaller than the density of the liquid. 63. .i new eE.I"Er-.'_t;ict.liaa'of1': Formula for eacl‘. substance and nanoscale pie ure: .- lfi] "Ei'ater H30 ['33 Nitrogen N} (33' {5 8 Q3 0 0' 63 C90 (5C1 I:ch Neon Xe [dj Chlorine ['13 T1. .l:351i'e::-'Etpfa.=rotion.' If the density of solid calcium is almost twice that of solid potassium. but their masses are approximately the same size. then the volume must account for the difference. This suggests that the atoms of calcium are smaller than the atoms of potassium: If \II/ \III/ \‘ ‘\ “\ “\ - Qf:§%:_ ./"\\\_. .7/LW ‘\ r N I: 'I i 'I i 'I i ll \_/’l\._/'\._/'k_/’ \J V \J V solid calcium solid potassium smaller atoms larger atoms closer packed less closely packed smaller volume larger volume S4. Aorta-er: (:1) Figures (:1), (b), and (f) (b) Figures (1:) and (i) (c) Figures (c). (d), and (g) Id} Figures {a}, {cl} and (f) (e) Figures (c) and (f) (1‘) Figures (a), (c). (d), and (f, (9 Figures {b}. (e), {g}. (11]., and (i) Sn’otegr and Espiononou: Ca} The figiu'es (a). (ls). and (f) look like the}: are in the solid state. The atoms or molecules are relatively close together and in a regular arrangement. (13} The figures (11) and (i) look like they are in the liquid state. The atoms are still pretty close together but tney are more randomly spaced and no longer in a regular arrangement. (c) The figures (c). Ld). and Lg) look like they are in the gas state. The atoms are fairly far apart and the}? are randomly spaced. ((1) The figures (a) and (d) look like they are samples of elements. The particles are atoms separated from each other. and the}: are all the same color. indicating that the}? are the .same time of atom. Figure (f) also shows diatomic molecules that are all the same color. this could also represent a diatomic element. {e} The figures (c) and (1‘) look like the}! are samples of compounds. The atoms are grouped in pairs resembling diatomic molecules that are all alike. (f) Zhe figures (a). (c). (d). and (f) look like the}: are samples of pure substances. The atoms or atom groups are all the same. (g) The figures (53). (e). (g), (h), and [i] look like they represent mixtures. They have different colors. different atom combinations. and-"or different phases. Chapter 2: Estoan and Elements 63. .ieou art-'Eapt'a'iinn'oe: A fee: common counting units are: pair (2]. dozen {12]. six-pack (a). gross {144-}. hundred (1 CID). million (LDCIIIIJIIDCIJ. billion {1.DCIIII.ICIDCI.CIEID]. etc. .' lChapter :: Chemi ca] Compounds 3-8. .ieou {b}, {c}, and (c) are ionic. S'nntegj' nndExplnea'n‘oii.‘ To tell if'a compound ionic or not. look for metals and nonmetals together. or common cations and anions. Ifa compound contains only nonmetals or metalloids and nonmetals. it is probably not ionic. [a] IC'FJr contains only nonmetals. Not ionic. I:th SrBr: has a metal and nonmetal together. Ionic. [c] C'ofiNCIsj} has a metal and nonmetals together. Ionic. (d) Sit); contains a metalloicl and a nonmetal. Not ionic. [e] KC}? has a metal and a common diatomic ion (CK—fin together. Ionic. [fj- SC]; contains only nonmetals. "Sat ionic. '1! Id . Anna“: {a} It? and DH— {11,132+ and 904:- tc) Na" and FD}— [tlju Til-If and {I— S'fi‘flrsglt' and Explanation ' Identify the common ions present in the compounds. [a] The ions present in a solution of KGI—I are K‘ and DH‘. I:th The ions present in a solution of ICES-CI; are H‘ and 5042‘. I:th The sons present in a solution ofh'a'hl03 are Na' and 303‘. I:th The ions present in a solution ofFI—Iqi'l are Iii-If and C1 ‘. Chapter 3: C'DF'filEDT Bondingr I-\_l An ionic bond and a covalent bond differ in the location of the electrons. In ionic bonds. there is no shanng of electrons. The cation is deficient in elections and the anion has extra electrons. The opposite charges of these ions cause them to be attracted to each other and that is what we call ionic bonding. In contrast. when both atotns want to gain electrons. they achieve this by sharing electrons. The atoms must stay close together to share electrons; hence a different [we of bond — a covalent bond — is fonned. To predict the type cfbonding. we need to determine n'hat types of elements are myolyed. Metals are not good at takingr electrons from other elements: nonmetals generally are good at taking electrons. If the elements differ in their ability to tal-ce electrons. such as metals and nonmetals. electrons will he transferred. so we'll predict ionic bonding. If they are similar. such as nonmetals and nonmetals. theyss'ill share. and we'll predict co'-.'alent bonding. (a) Na is a metal and I: is a nonmetal. The nonmetal can take elections from the metal. so we predict ionic bonding. (h:- C' is a nonmetal and S is a nonmetal. They hotl‘. want to take electrons. so we predict co'-.'alent bonding. (c) Mg is a metal and BI: is a nonmetal. The nonmetal can take elections from the metal. so we predict ionic bonding. (:1:- P4 is a nonmetal and Cl; a nonmetal. They both want to take electrons. so we predict coyalent bonding. ...
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This note was uploaded on 06/03/2008 for the course CHEM 1A taught by Professor Nitsche during the Fall '08 term at University of California, Berkeley.

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MOOREHW1 - lESL-:apter 1: The Katine of Chemistry 45....

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