Qhov Tseem Ceeb Qhov txawv - Hydrate vs Anhydrate
Ob lo lus "hydrate" thiab "anhydrate" yog ob lo lus sib txawv hauv lawv lub ntsiab lus, thiab qhov sib txawv tseem ceeb ntawm hydrate thiab anhydrate yog tias hydrates yog cov ionic compounds uas muaj cov dej dawb molecules thaum anhydrates yog cov tebchaw uas tsis muaj dawb dej molecules. Hydrates yog tsim los ntawm ionic compounds thaum lawv raug huab cua, reacting nrog dej molecules. Anhydrates yog qhov sib txawv version ntawm hydrates; lawv tsis muaj dej molecules. Anhydrates tseem hu ua cov tshuaj ziab khaub ncaws los yog desiccants.
Hydrates yog dab tsi?
Dej tuaj yeem suav tias yog qhov sib xyaw ntau tshaj plaws hauv ntiaj teb. Thaum cov tshuaj sib xyaw ua ke raug rau saum huab cua, dej vapor hauv huab cua yog adsorbed rau cov molecules. Nws tuaj yeem yog cov tshuaj tiv thaiv saum npoo los yog kev hloov kho ntawm tag nrho cov qauv tshuaj tsim cov tshuaj lom neeg nrog dej. Feem ntau, cov dej molecules raug khi rau cations hauv cov khoom ionic. Qhov tshwm sim no hu ua "hydration."
Muaj ntau ionic compounds tam sim no nyob rau hauv daim ntawv hydrated; Qee qhov piv txwv yog Gypsum (CaSO42H2O), Borax (Na3B 4O710H2O), thiab Epsom ntsev (MgSO4 7H2O). Tus naj npawb ntawm cov dej molecules nyob rau hauv hydrates nws txawv los ntawm ib tug compound mus rau lwm yam nyob rau hauv stoichiometric cov nyiaj. Cov mis mos molecular ntawm ib tug hydrate compound yog ib tug ua ke ntawm molecular mis ntawm cov anhydrous compound thiab tus naj npawb ntawm molecules ib mole nyob rau hauv lub hydrate. Ob qho no tau sib cais siv "dot"; ib qho piv txwv yog muab hauv qab no.
Lub npe dav dav: Epsom ntsev thiab tshuaj npe: Magnesium Sulphate Heptahydrate.
Ib qho piv txwv ntawm heptahydrate ntawm magnesium sulfate
Dab tsi yog Anhydrates?
Anhydrates tseem hu ua cov khoom tsis muaj dej; lawv tsis muaj cov dej molecule li hauv hydrates. Nyob rau hauv pawg no, cov dej molecules raug tshem tawm los ntawm cua sov lub compound mus rau qhov kub siab los yog nqus. Feem ntau, anhydrates tuaj yeem siv los ua cov tshuaj ziab khaub ncaws, vim tias lawv tuaj yeem nqus dej molecules los ntawm ib puag ncig. Silica gel yog ib qho ntawm feem ntau siv anhydrates. Ib pob ntawv ntawm silica gel khaws cia hauv ntau cov khoom tiav kom nqus dej. Nws pab kom cov cheeb tsam ib puag ncig qhuav, thiab nws tiv thaiv kev loj hlob ntawm pwm.
Silica Gel hlaws
Dab tsi yog qhov txawv ntawm Hydrate thiab Anhydrates?
Definition of Hydrates thiab Anhydrates
Anhydrates: Anhydrates (tseem hu ua cov neeg ua kom qhuav lossis desiccants) yog cov tebchaw uas tsis muaj cov dej dawb molecules.
Hydrates: Cov dej yog cov ionic compounds uas muaj cov dej dawb molecules.
Txoj kev tsim cov dej thiab cov dej tsis huv
Anhydrates: Cov dej tsis huv yog tsim los ntawm kev tshem tawm cov dej molecules ywj pheej los ntawm kev nqus los yog cua sov rau qhov kub siab dua.
Hydrates: Hydrate compounds yog tsim lawm thaum lawv raug huab cua. Lawv yog tag nrho cov ionic compounds uas yog tsim los ntawm kev sib txuas nrog cov gaseous dej molecules nyob rau hauv cov huab cua. Qhov kev sib cog lus yog tsim los ntawm cov cation ntawm cov molecule thiab cov dej molecule.
Cov Khoom Ntawm Cov Dej thiab Cov Tsis Muaj Dej
Anhydrates: Anhydrates raug suav tias yog cov tshuaj ziab khaub ncaws vim lawv muaj peev xwm nqus dej molecules los ntawm ib puag ncig. Cov dej molecules tuaj yeem tshem tau yooj yim los ntawm cua sov kom kub.
Hydrates: Feem ntau, cov dej molecules hauv hydrates tuaj yeem raug tshem tawm los ntawm cua sov. Cov khoom tau txais tom qab cua sov yog cov anhydrous compound; nws muaj cov qauv sib txawv ntawm cov hydrate.
Example:
CuSO4. 5H2O → CuSO4 + 5H2O
(Blue) (White)
Tus naj npawb ntawm cov dej molecules dai hauv hydrate crystals txawv vim nws kuj ua raws li txoj cai stoichiometric piv. Tus naj npawb ntawm cov molecules suav nrog hauv cov qauv molecular yog raws li hauv qab no.
| Prefix | Tsis muaj dej molecules | Molecular formula | Npe |
| Mono- | 1 | (NH4)C2O4. H2O | YAmmonium oxalate monohydrate |
| Di- | 2 | CaCl2.2H2O | Calcium chloride dihydrate |
| Tri- | 3 | 2H3O3.3H2 O | Sodium acetate trihydrate |
| Tetra- | 4 | FePO4.4H2O | Iron (III) phosphate tetrahydrate |
| Penta | 5 | CuSO4.5H2O | tooj liab (II) sulphate pentahydrate |
| Hexa | 6 | CoCl2.6H2O | Cobolt(II) chloride hexahydrate |
| Hepta | 7 | MgSO4.7H2O | Magnesium sulphate heptahydrate |
| octa | 8 | BaCl2.8H2O | Barium hydroxide octahydrate |
| Deca | 10 | Na2CO3.10H2O | Sodium carbonate decahydrate |
Image Courtesy: "Silica gel pb092529" los ntawm Wiebew - Tus kheej ua haujlwm. (CC BY-SA 3.0) ntawm Wikimedia Commons "Magnesium sulfate heptahydrate". (Public Domain) ntawm Wikimedia Commons
