Kutentha kwa mapangidwe - ndi chiyani ichi?

Timanena za chiyani kutentha kwa mapangidwe, komanso chimatanthauza zinthu zimene otchedwa muyezo. Pofuna kuthetsa nkhaniyi, kupeza kusiyana zinthu yosavuta zovuta kunja. Kulimbitsa maganizo "kutentha kwa mapangidwe", ganizirani yeniyeni mankhwala aone kuti pali.

Muyezo enthalpy mapangidwe zinthu

76 KJ mphamvu anamasulidwa mu zimene mpweya ndi anzake mpweya wa hydrogen. Pankhaniyi, zimakwana - ndi zotsatira matenthedwe wa mankhwala anachita. Koma izi kutentha kwa mapangidwe tinthu dziko ku zinthu zophweka. "Chifukwa chiyani?" - Inu kufunsa. Ichi ndi chifukwa chakuti zigawo kuyambira ali mpweya ndi wa hydrogen. 76 KJ / mol ndi mphamvu kuti akatswiri amatchedwa "kutentha kwa mapangidwe".

Mapepala Data

Mu thermochemistry kulibe matebulo ambiri, amene ali kutentha kwa mapangidwe zosiyanasiyana zinthu mankhwala kwa zinthu zophweka. Mwachitsanzo, kutentha kwa mapangidwe thunthu, njira imene NKHA ₂ m'chigawo gaseous ali ndi chithunzi 393,5 KJ / mol.

kufunika othandiza

N'chifukwa chiyani deta mfundo? Kutentha kwa mapangidwe - mtengo, amene ntchito pa mawerengedwe a zotsatira matenthedwe njira mankhwala aliwonse. Pofuna kuchita kuwerengetsera ngati kugwiritsa ntchito lamulo la thermochemistry.

thermochemistry

Ndi lamulo lofunika limene limafotokoza njira mphamvu anati mu njira ya mankhwala anachita. Pa mogwirizana anaona kusintha Mkhalidwe mu dongosolo yomweyo. Ena zinthu kutha, zigawo latsopano kuonekera mu malo awo. Zimenezi limodzi ndi kusintha mu mphamvu mkati mwa dongosolo, imasonyezedwa mu mawonekedwe a ntchito kapena kutentha. ntchito, amene amagwirizana ndi kutambasuka, pakuti zosiyanasiyana zimachitikira ndi chithunzi kuthungo. Kutentha anamasulidwa mu kutembenuka kwa chimodzi mu chinthu china chikhoza kukhala wamtengo wapatali.

Ngati tikambirana zosiyanasiyana masinthidwe, pafupifupi pali mayamwidwe kapena kumasulidwa kwa wina kuchuluka kwa kutentha. thermochemistry - gawo lapadera wakhala analengedwa kuti mudziwe chododometsa.

Chilamulo Hess wa

Chifukwa lamulo loyamba yopezeka m'zinthu zachilengedwe, kunakhala kotheka kuti achite mawerengedwe a zotsatira matenthedwe malinga ndi zikhalidwe za mankhwala anachita. kuwerengetsera zochokera m'chilamulo thermochemistry chachikulu, ndicho chilamulo cha Hess. Tiyeni chiphunzitso chake: matenthedwe zotsatira mankhwala kusintha zokhudza chikhalidwe, woyamba ndi womaliza boma la zinthu, si kugwirizana ndi njira mogwirizana.

Kodi motere ku chiphunzitso ichi? Mu nkhani ya mankhwala ena siziyenera okhawo chimake imodzi mogwirizana ndi zimene zikhoza kuchitidwa mu njira zosiyanasiyana. Mulimonse, ziribe kanthu momwe inu kupereka chuma anakhumba, zotsatira matenthedwe njira yake idzakhala zikutsatiridwa phindu. Kuthandauza m'pofunika kuti afotokoze zotsatira matenthedwe wa masinthidwe wapakatikati. Chifukwa chilamulo cha Hess anakhala zotheka kuchita kuwerengetsera wa tochepa zotsatira ikukhudzana n'zosatheka kuchita calorimeter lapansi. Mwachitsanzo, kuchuluka kutentha kwa mapangidwe mpweya monoxide zinthu masamu ndi lamulo Hess koma ndi kuyesera chizolowezi kudziwa inu sadzapambana. Choncho n'kofunika wapadera thermochemical matebulo imene mfundo n'zosangalatsa kumva m'kabokosi ka mankhwala osiyanasiyana linanena m'mikhalidwe muyezo

mfundo zofunika mu mawerengedwe a

Popeza kuti kutentha kwa mapangidwe - ndi kutentha zotani, chofunika kwambiri ndi boma akaphatikiza wa thunthu mu funso. Mwachitsanzo, pamene mukumwa miyezo akuti ndi muyezo boma mpweya graphite, m'malo diamondi. Komanso kuganizira kuthamanga ndi kutentha, ndiye zinthu zimene poyamba yatikhudza zigawo zikuluzikulu. Izi zedi thupi amatha mphamvu kwambiri pa zimene, ndi kuchuluka kapena yafupika kuchuluka kwa mphamvu. Kuti agwire kuwerengetsera zofunika thermochemistry kugwiritsa ntchito zizindikiro konkire kuthamanga ndi kutentha.

zinthu muyezo

Chifukwa cha kutentha kwa mapangidwe nkhani - kufuna zotsatira za mphamvu ndi pa zinthu muyezo kusiyanitsa padera. Kutentha wasankhidwa kuti mawerengedwe a 298K (madigiri 25 centigrade) Anzanu - 1 mlengalenga. Komanso, mfundo yofunika kwambiri, yomwe ifunika powasamalira n'chakuti, kutentha kwa mapangidwe kwa zinthu aliyense yosavuta ndi ziro. Zimenezi n'zomveka, chifukwa zinthu yosavuta musati kupanga okha, ndiye palibe mowa mphamvu asayembekezere.

mfundo za thermochemistry

Chigawo chino zimapangidwira ano ali ndi tanthauzo lapadera, chifukwa apa ikuchitika kuwerengetsera zofunika zotsatira ntchito mphamvu za matenthedwe. Mu thermochemistry, pali mawu ambiri ndi mfundo zimene zili zofunika ntchito kuti zotsatira ankafuna. The enthalpy (H) akusonyeza kuti mankhwala anachita zinachitika mu dongosolo chatsekedwa, panalibe mphamvu pa yankho ku reactants ena anzawo zinali zonse. mafotokozedwe Zimenezi zimathandiza kulankhula za lolondola kuwerengetsera anachita.

Malinga mtundu zotani zomwe amati, ukulu ndi chizindikiro cha chifukwa zotsatira matenthedwe zingasiyane kwambiri. Choncho, kutembenuza zonse zokhudza kuwonongeka kwa zinthu zovuta m'zigawo angapo ophweka, amaganiza kutentha mayamwidwe. Kulumikiza ndi kuchuluka kwa zipangizo anachita kuyambira mu mankhwala ovuta kwambiri limodzi ndi kutuluka kwa ndalama zochuluka mphamvu.

Pomaliza

Pothetsa vuto lililonse thermochemical ntchito aligorivimu chomwecho zochita. Choyamba, tebulo anatsimikiza aliyense chigawo yoyambira, komanso mankhwala anachita kuchuluka kwa kutentha kwa mapangidwe, osati ndikuiwala boma akaphatikiza. Kenako, zida Hess malamulo salisiyanitsa kudziwa zedi osadziwika.

chidwi ziperekedwe kwa chifukwa chakuti stereochemical linalipo thunthu koyamba kapena komaliza mu aone kuti pali makamaka. Ngati anachita ndi zinthu zophweka, kutentha awo muyezo mapangidwe ndi wofanana ndi ziro, i.e., zigawo zikuluzikulu ziribe mphamvu pa zotsatira akamagwira kuwerengetsera. Yesani kugwiritsa ntchito mfundo pa zimachitika yeniyeni. Ngati timatenga chitsanzo cha ndondomeko ya mapangidwe chitsulo okusayidi (Fe ³⁺⁾ woyenga zitsulo mwa kuchita ndi graphite ndi yofunika kutchulidwa angapezeke heats muyezo mapangidwe. Pakuti chitsulo okusayidi (Fe ³⁺⁾ zidzakhala -822,1 KJ / mol kwa graphite (yosavuta mankhwala) ndi ziro. Zimene chifukwa umabala mpweya monoxide (NKHA), amene chizindikiro ali ndi ubwino - 110,5 KJ / mol, pamene kutentha kwa mapangidwe anamasulidwa chitsulo limafanana ndi ziro. Kujambulitsa heats muyezo wa mapangidwe zimachitika izi mankhwala amakhala motere:

_About 298 H = 3 × (-110,5) -? (-822,1) = -331,5 + 822,1 = 490,6 KJ.

KUSANTHULA akamagwira malamulo Hess chifukwa M'ndandanda, ndi kupanga kwanzeru kuti ndondomeko ndi kutembenuka endothermic, i.e. kukutanthauza zatrachivaniya kuchepetsa mphamvu chitsulo zimene okusayidi ake ferric.