Qhov sib txawv tseem ceeb ntawm molecule thiab lattice yog tias lub molecule muaj cov atoms sib txuas rau ib leeg whereas lattice muaj atoms, molecules lossis ions sib txuas rau ib leeg.
Atoms koom ua ke los tsim ntau yam tshuaj lom neeg. Raws li lawv txoj kev npaj, lawv cov khoom hloov pauv. Chav tsev yooj yim tshaj plaws uas tuaj yeem tsim tau thaum atoms khi nrog ib leeg yog ib qho molecule. Yog hais tias muaj coob tus atoms, ions los yog molecules ua ke nrog ib leeg, ces qhov tshwm sim yog ib tug lattice. Lub lattice muaj cov qauv txiav txim siab heev thiab cov molar loj heev.
Molecule yog dab tsi?
Molecules muaj cov tshuaj sib khi ob lossis ntau lub atoms ntawm tib lub caij (e.g., O2, N2) lossis lwm yam (H2O, NH 3). Molecules tsis muaj nqi, thiab cov atoms khi nrog ib leeg ntawm covalent bonds. Ntxiv mus, lawv tuaj yeem loj heev (haemoglobin) lossis me me (H 2), nyob ntawm seb muaj pes tsawg tus atoms uas txuas nrog ib leeg.
Daim duab 01: Ib Lub Dej Molecule
Cov mis molecular ntawm ib lub molecule qhia hom thiab tus naj npawb ntawm atoms hauv ib lub molecule. Cov mis empirical muab qhov yooj yim tus lej piv ntawm atoms tam sim no nyob rau hauv ib lub molecule. Piv txwv li, C6H12O6 yog tus qauv molecular ntawm qabzib, thiab CH. 2O is the empirical formula. Molecular mass yog qhov loj uas peb suav suav nrog tag nrho cov atoms hauv cov mis molecular. Tsis tas li ntawd, txhua molecule muaj nws tus kheej geometry. Ntxiv mus, cov atoms nyob rau hauv ib tug molecule npaj nyob rau hauv ib tug ruaj khov yam ntxwv nrog ib tug tshwj xeeb daim ntawv cog lus lub kaum sab xis thiab daim ntawv cog lus ntev kom txo tau cov repulsions thiab strain rog.
Dab tsi yog Lattice?
Lattice yog lub network loj ntawm atoms uas muaj cov qauv txiav txim. Hauv chemistry, peb tuaj yeem pom ntau hom ionic thiab covalent lattices. Peb tuaj yeem txhais lub lattice raws li cov khoom uas muaj peb-dimensional kev txiav txim ntawm cov chav hauv paus. Chav tsev yooj yim tuaj yeem yog atom, molecule lossis ion. Yog li, lattices yog crystalline lug nrog cov txheej txheem rov ua dua.
Tsis tas li ntawd, yog tias lub network no muaj ions koom nrog ionic bonds, peb hu lawv ua ionic crystals. Piv txwv li, sodium chloride yog ionic lattice. Sodium yog ib pawg 1 hlau, yog li tsim ib qho +1 them cation raws li nws cov cation ruaj khov tshaj plaws. Chlorine yog ib qho nonmetal thiab muaj peev xwm tsim tau ib qho -1 them anion. Nyob rau hauv lub lattice, rau chloride ions nyob ib ncig ntawm txhua sodium ion thiab vice versa. Vim tag nrho cov electrostatic attraction ntawm ions, lub lattice qauv yog ruaj khov heev. Tus naj npawb ntawm ions tam sim no nyob rau hauv lub lattice nws txawv nrog qhov loj ntawm nws. Lattice zog los yog enthalpy ntawm lub lattice yog qhov ntsuas ntawm lub zog ntawm cov ionic bonds hauv cov lattice. Nquag lattice enthalpy yog exothermic.
Daim duab 02: Sodium Chloride Lattice Structure
Pob zeb diamond thiab quartz yog ob qho piv txwv ntawm peb-dimensional covalent lattices. Pob zeb diamond tsuas yog muaj cov pa roj carbon atom xwb, thiab txhua cov pa roj carbon atom covalently khi rau plaub lwm cov pa roj carbon atoms los tsim cov qauv lattice. Yog li txhua carbon atom muaj tetrahedral kev npaj. Pob zeb diamond muaj kev ruaj ntseg siab vim qhov qauv no. (Pob zeb diamond yog ib qho ntawm cov khoom muaj zog tshaj plaws hauv ntiaj teb.) Quartz lossis silicon dioxide kuj muaj covalent bonds, tab sis cov nyiaj no muaj nyob nruab nrab ntawm silicon thiab oxygen atoms (lattice ntawm txawv atoms). Ob leeg ntawm cov lattices covalent no muaj qhov melting point siab heev, thiab lawv ua tsis tau hluav taws xob.
Qhov txawv ntawm Molecule thiab Lattice yog dab tsi?
Ib daim ntawv molecule thaum ob lossis ntau lub atoms khi nrog ib leeg los ntawm covalent chemical bonds lossis ionic bonds. Ntawm qhov tod tes, cov ntaub ntawv lattice thaum muaj ntau cov atoms, molecules lossis ions sib txuas nrog ib leeg los tsim cov qauv sib txuas. Yog li, qhov sib txawv tseem ceeb ntawm cov molecule thiab lattice yog cov molecules muaj cov atoms sib txuas rau ib leeg whereas lattices muaj atoms, molecules lossis ions sib txuas rau ib leeg.
Raws li lwm qhov sib txawv tseem ceeb ntawm molecule thiab lattice, peb tuaj yeem hais tias molecule tuaj yeem tshwm sim ua cov khib nyiab, kua lossis roj thaum lattices tshwm sim tsuas yog cov khoom siv. Ntxiv mus, qhov loj ntawm ib lub molecule yog tsawg heev piv rau qhov loj ntawm lub lattice vim hais tias tus naj npawb ntawm atoms nyob rau hauv ib tug lattice yog sib piv heev.
Ntau qhov sib txawv tau pom hauv qab no hauv infographic ntawm qhov sib txawv ntawm molecule thiab lattice.
Summary – Molecule vs Lattice
Molecules thiab lattices yog ob lo lus tseem ceeb hauv chemistry. Lawv txawv ntawm ib leeg; yog li peb tsis tuaj yeem siv lawv sib pauv. Qhov sib txawv tseem ceeb ntawm cov molecule thiab lattice yog cov molecules muaj cov atoms sib koom ua ke thaum lattices muaj atoms, molecules lossis ions sib txuas rau ib leeg.
