Giri\u015f
\nEnerjinin korunumunu ve d\u00f6n\u00fc\u015f\u00fcm\u00fcn\u00fc inceleyen bilim koluna termodinamik denir( Termodinamik ad\u0131, Grek\u00e7e “therme” (\u0131s\u0131) ve “dynamis” (i\u015f) s\u00f6zc\u00fcklerinden t\u00fcretilmi\u015ftir). Bu bilim kolu 19. y\u00fczy\u0131ldaki End\u00fcstri Devrimine ba\u011fl\u0131 olarak do\u011fmu\u015f, \u0131s\u0131 makinalar\u0131n\u0131n verimini artt\u0131rmak i\u00e7in yap\u0131lan \u00e7al\u0131\u015fmalar, \u0131s\u0131, i\u015f ve yak\u0131tlar\u0131n \u0131s\u0131 i\u00e7eri\u011fi kavramlar\u0131n\u0131 \u00f6ne \u00e7\u0131karm\u0131\u015ft\u0131r. Bu bilim kolu, 1920lerde geli\u015ftirilen yeni kuantum kuram\u0131 \u0131\u015f\u0131\u011f\u0131nda baz\u0131 de\u011fi\u015fmelere u\u011fram\u0131\u015f, istatistiksel termodinamik do\u011fmu\u015ftur. Bug\u00fcn bir \u00e7ok kimyasal olay, termodinami\u011fin yasalar\u0131 \u0131\u015f\u0131\u011f\u0131nda yorumlanmaktad\u0131r.
\n\u0130nsan\u0131n do\u011faya egemenlik m\u00fccadelesindeki en b\u00fcy\u00fck \u00e7abalardan birisi, enerjiyi yararl\u0131 bir \u015fekilde kullanmak (i\u015fe \u00e7evirmek) olmu\u015ftur.
\nTemel Kavramlar: Evren, Sistem ve \u00c7evre
\nEvren, do\u011fan\u0131n t\u00fcm\u00fcn\u00fc kapsar. \u0130nceleyebildi\u011fimiz evren par\u00e7as\u0131na sistem, sistemin i\u00e7inde bulundu\u011fu ko\u015fullara da \u00e7evre diyoruz. Sistem, \u00e7evresi ile yal\u0131t\u0131lm\u0131\u015f, \u00e7evresiyle enerji ve madde al\u0131\u015f veri\u015fi olmayan evren par\u00e7as\u0131d\u0131r. \u00d6rne\u011fin 1.1 \u015eekilde bir kesiti verilen silindirdeki hidrojen gaz\u0131 (H2), ve oksijen gaz\u0131 (O2) kar\u0131\u015f\u0131m\u0131n\u0131 alal\u0131m. Burada sistem, H2 ve O2 kar\u0131\u015f\u0131m\u0131d\u0131r; silindir, piston ve onlar\u0131n yan\u0131ndaki her \u015fey \u00e7evreyi olu\u015fturur. Hidrojen ve oksijen tepkimeye girip su olu\u015ftururken, enerji a\u00e7\u0131\u011fa \u00e7\u0131kar. Bu tepkimeye ayn\u0131 zamandan hidrojenin yanma tepkimesi olarak da bakabiliriz.
\n2H2 (g) + O2 (g) \u00be\u00ae 2H2O (s) + enerji
\nBu kimyasal tepkime s\u0131ras\u0131nda sistemi olu\u015fturan hidrojen ve oksijen atomlar\u0131n\u0131n kimyasal \u015fekli de\u011fi\u015fmi\u015f, sistemden madde \u00e7\u0131k\u0131\u015f\u0131 veya sisteme madde giri\u015fi olmam\u0131\u015ft\u0131r. Buna kar\u015f\u0131n sistem ile \u00e7evresi aras\u0131nda \u0131s\u0131 ve i\u015f de\u011fi\u015fimi olmu\u015ftur. Bunlar da \u00f6l\u00e7\u00fclebilir niceliklerdir.
\nEnerjinin \u015eekilleri
\nEnerji ilke olarak iki tipte s\u0131n\u0131flan\u0131r: kinetik enerji ve potansiyel enerji. Kinetik enerji hareket enerjisidir. K\u00fctlesi m, h\u0131z\u0131 v ile simgelenen bir nesnenin kinetik enerjisi, k\u00fctlesi ile h\u0131z\u0131n\u0131n karesinin \u00e7arp\u0131m\u0131n\u0131n yar\u0131s\u0131na e\u015fittir.<\/p>\n
* Uluslararas\u0131 birim sisteminde (SI) enerji birimi joule (J) d\u00fcr. Kilojoule (kJ) de\u011feri 4.18 e b\u00f6l\u00fcn\u00fcrse kilokalori elde edilir.
\n* Baz\u0131 niceliklerin son ve ilk miktarlar\u0131 aras\u0131ndaki fark, Grek’\u00e7e delta, (D ) harfi ile g\u00f6sterilir.<\/p>\n
* Enerji Birimleri
\n* Joule (J): 1J = 1 kg \u2013 m2, olan bir nesnenin kinetik enerjisine 1 J denir.
\n* Kalori (kal): 14.5 0C deki 1 g suyun s\u0131cak\u0131l\u011f\u0131n\u0131 15.5 0C ye \u00e7\u0131karmak i\u00e7in gereken enerji 1 kaloridir.
\n1000 kal = 1 Kkal ve 1 kalori = 4.184 joule
\nIs\u0131 Kapsam\u0131 ve S\u0131cakl\u0131k
\nKimyasal de\u011fi\u015fmelerdeki enerji de\u011fi\u015fimi \u00e7ok kere \u0131s\u0131 enerjisi olarak kendini g\u00f6sterir.
\nBir maddenin belli bir s\u0131cakl\u0131k aral\u0131\u011f\u0131nda (D T) ald\u0131\u011f\u0131 ya da sald\u0131\u011f\u0131 \u0131s\u0131 enerjisine, (q) \u0131s\u0131 kapsam\u0131 denir.
\nIs\u0131 kapsam\u0131 = q \/ D T
\nIs\u0131 kapsam\u0131, \u00e7ok kere \u00f6zg\u00fcl \u0131s\u0131 ya da molar \u0131s\u0131 kapsam\u0131 olarak belirtilir. Bir maddenin bir gram\u0131n\u0131n s\u0131cakl\u0131\u011f\u0131n\u0131 bir kelvin (1\u00b0 C ye e\u015fde\u011ferdir) art\u0131rmak i\u00e7in gereken \u0131s\u0131 miktar\u0131na \u00f6zg\u00fcl \u0131s\u0131 denir. Molar \u0131s\u0131 kapsam\u0131 ise bir mol maddenin s\u0131cakl\u0131\u011f\u0131n\u0131 bir kelvin art\u0131rmak i\u00e7in gereken \u0131s\u0131 miktar\u0131d\u0131r. S\u0131cakl\u0131k bir maddedeki yap\u0131ta\u015flar\u0131n\u0131 olu\u015fturan par\u00e7ac\u0131klar\u0131n herbirinin ortalama kinetik enerjisiyle orant\u0131l\u0131 bir niceliktir. Is\u0131 kapsam\u0131, bir kapasite \u00f6zelli\u011fidir, yani madde miktar\u0131na ba\u011fl\u0131d\u0131r. S\u0131cakl\u0131k ise bir \u015fiddet \u00f6zelli\u011fidir ve madde miktar\u0131na ba\u011fl\u0131 de\u011fildir.<\/p>\n
8.1 K\u0130MYASAL TEPK\u0130MELER VE ENERJ\u0130
\nKimyasal de\u011fi\u015fmeler, hep enerji al\u0131\u015f veri\u015fiyle ger\u00e7ekle\u015fir. Yanma olaylar\u0131, bir kimyasal de\u011fi\u015fmedir ve \u0131s\u0131, \u0131\u015f\u0131k bi\u00e7imlerinde enerji a\u00e7\u0131\u011fa \u00e7\u0131kararak olu\u015fur. \u015eekerin v\u00fccudumuzda yan\u0131nca enerji verdi\u011fini (\u0131s\u0131 a\u00e7\u0131\u011fa \u00e7\u0131kard\u0131\u011f\u0131n\u0131) biliriz. Suda daha \u00e7ok \u015feker ya da tuz \u00e7\u00f6zmek i\u00e7in, \u00e7\u00f6zeltiyi \u0131s\u0131tmak, yani sisteme enerji vermek gerekir. Yine suyu elektrolizle hidrojen ve oksijen elementlerine ayr\u0131\u015ft\u0131rmak i\u00e7in sisteme enerji verilmelidir.
\nH2O (s) \u00be \u00ae H2 (g) + 1\/2 O2 (g)
\nKimyasal tepkimeler iki ko\u015fulda ger\u00e7ekle\u015febilir:
\n1. Sabit hacimde (kapal\u0131 bir kapta)
\n2. Sabit bas\u0131n\u00e7ta (pistonlu bir kapta)
\nBu iki ko\u015fuldaki enerji de\u011fi\u015fmelerinin ayn\u0131 olmad\u0131\u011f\u0131n\u0131 g\u00f6rece\u011fiz.
\nKimyasal tepkimelerdeki enerji de\u011fi\u015fimleri, temelde ba\u011f enerjilerindeki de\u011fi\u015fmedir. Onun i\u00e7in \u00f6nce ba\u011f enerjilerini inceleyece\u011fiz.
\n8.2 BA\u011eLARIN KIRILMASI VE BA\u011e ENERJ\u0130LER\u0130
\nKimyasal tepkimeler, atomlar ya da iyonlar aras\u0131ndaki kimi ba\u011flar\u0131n k\u0131r\u0131lmas\u0131 ve yeni ba\u011flar\u0131n olu\u015fmas\u0131na dayan\u0131r. Atomlar ya da iyonlar ba\u011flan\u0131rken daima enerji a\u00e7\u0131\u011fa \u00e7\u0131kar; bir ba\u011f\u0131 k\u0131rmak i\u00e7in ise maddeye enerji verilmesi gerekir. Gaz faz\u0131ndaki iki atomun ba\u011flanmas\u0131yla a\u00e7\u0131\u011fa \u00e7\u0131kan ya da bu ba\u011f\u0131 k\u0131rmak i\u00e7in gereken enerjiye ba\u011f enerjisi denir. 1.1. Tabloyu inceleyiniz.
\nH (g) + H (g) \u00be \u00ae H2 (g) + 436 kJ\/mol
\nBu tepkimeye g\u00f6re, 1 mol H2 (g) molek\u00fcl\u00fc atomlar\u0131ndan olu\u015furken (432 kJ) a\u00e7\u0131\u011fa \u00e7\u0131kar. Ayn\u0131 ko\u015fullarda 1 mol H\u2013H ba\u011f\u0131n\u0131 k\u0131rmak i\u00e7in ayn\u0131 miktar enerji gerekir:
\nH2 (g) + 432 kJ\/mol \u00be \u00ae H (g) + H (g)
\nBa\u011f enerjileri, kimyasal ba\u011f\u0131n ne derece kuvvetli oldu\u011funun bir \u00f6l\u00e7\u00fcs\u00fcd\u00fcr. Ayn\u0131 iki atom aras\u0131ndaki ikili ve \u00fc\u00e7l\u00fc ba\u011flar\u0131n enerjileri birli ba\u011flardan b\u00fcy\u00fckt\u00fcr. F – F, O = O ve N N ba\u011flar\u0131n\u0131 k\u0131rmak i\u00e7in s\u0131ras\u0131yla155, 494 ve 942 kJ\/mol gerekir. \u015eimdi ba\u011f enerjilerinin kimyasal tepkimelerdeki kullan\u0131m\u0131na bakal\u0131m.
\nH \u2013 H (g) + F \u2013 F (g) \u00be \u00ae 2 (H \u2013 F) (g) tepkimesinde k\u0131r\u0131lan ba\u011flar: H \u2013 H ve F \u2013 F ba\u011flar\u0131d\u0131r. Ba\u011flar\u0131 k\u0131rmak i\u00e7in enerji veririz. Olu\u015fan ba\u011flar, iki H \u2013 F ba\u011f\u0131d\u0131r. Ba\u011f olu\u015funca enerji al\u0131r\u0131z. Verilen ve al\u0131nan enerjilerin fark\u0131 tepkimenin ba\u011f entalpisini (enerji blan\u00e7osunu) g\u00f6sterir. Ba\u011flar\u0131 k\u0131rmak i\u00e7in 432+ 155 = 587 kJ\/mol gerekir; iki H \u2013 F ba\u011f\u0131 olu\u015furken 2 x 565 = 1130 kJ\/mol a\u00e7\u0131\u011fa \u00e7\u0131kar(ekzotermik). Net sonu\u00e7 1130 \u2013 585 = 545 kJ\/mol’d\u00fcr.
\nH2 (g) + F2 (g) \u00be \u00ae 2HF (g) + 545 kJ\/mol (D H = -131 Kkal\/mol)
\n8.1 \u00d6RNEK
\nH Cl
\nH \u2013 C \u2013 H (g) + 4 (Cl \u2013 Cl) (g) \u00be \u00ae Cl \u2013 C \u2013 Cl (g) + 4 (H \u2013 Cl) (g)
\nH Cl
\ntepkimesinin ba\u011f enerjisini hesaplay\u0131n\u0131z.
\nBa\u011f enerjileri (kJ\/mol):
\nC \u2013 H :411; Cl \u2013 Cl : 240
\nC \u2013 Cl : 327; H \u2013 Cl : 428
\n\u00c7\u00f6z\u00fcm
\nK\u0131r\u0131lan ba\u011flar Olu\u015fan ba\u011flar
\n4 (C \u2013 H) : 4 x 411 = 1644 4 (C \u2013 Cl) : 4 x 327 = 1308
\n4 (Cl \u2013 Cl) : 4×240 = 960 4 (H \u2013 Cl) : 4 x 428 = 1712
\n2604 3020
\nA\u00e7\u0131\u011fa \u00e7\u0131kan enerji daha b\u00fcy\u00fck oldu\u011fu i\u00e7in tepkime ekzotermiktir.
\n3020 \u2013 2604 = 416 kJ
\nCH4 (g) + 4 Cl2 (g) \u00be \u00ae CCl4 (g) + 4HCl (g) + 416 kJ\/mol
\n8.1 TABLO Ba\u011f Enerjileri<\/p>\n
Baz\u0131 atomlar (C, N, O ve S) kendileriyle ya da ba\u015fkalar\u0131yla ikili ve \u00fc\u00e7l\u00fc ba\u011flarla ba\u011flanabilir. \u00d6rne\u011fin oksijen molek\u00fcl\u00fcn de (O2) ikili ba\u011f, azot molek\u00fcl\u00fcnde (N2) \u00fc\u00e7l\u00fc ba\u011f vard\u0131r.<\/p>\n
\u0130kili ba\u011f i\u00e7eren \u00dc\u00e7l\u00fc ba\u011f i\u00e7eren
\nbaz\u0131 molek\u00fcller baz\u0131 molek\u00fcller
\nOksijen, O = O Azot N ::: N
\nEtilen H2C = CH2 Hidrojen siyan\u00fcr H \u2013 C::: N
\nFormaldehit H \u2013 C = O Asetilen H \u2013 C :::C \u2013 H
\nH
\n8.2 \u00d6RNEK
\nA\u015fa\u011f\u0131daki ba\u011f enerjilerine g\u00f6re tepkimenin enerji de\u011fi\u015fimini hesaplay\u0131n\u0131z.
\nH \u2013 H : 436 kJ\/mol; C = C : 619 kJ\/mol
\nC \u2013 C : 348 kJ\/mol; C \u2013 H : 413 kJ\/mol
\nH H
\nH \u2013 C = C \u2013 H + H \u2013 H \u00be \u00ae H \u2013 C \u2013 C \u2013 H
\nH H H H
\n\u00c7\u00f6z\u00fcm
\nBa\u011f enerjileri, o ba\u011f\u0131 k\u0131rmak i\u00e7in gereken veya o ba\u011f\u0131n olu\u015fmas\u0131 s\u0131ras\u0131nda a\u00e7\u0131\u011fa \u00e7\u0131kan enerjilerdir. Verilen tepkimede bir C = C ba\u011f\u0131 ile bir H \u2013 H ba\u011f\u0131 kopar\u0131lacak \u0131s\u0131 alan i\u015flemler); buna kar\u015f\u0131n bir C \u2013 C ba\u011f\u0131 ve iki C \u2013 H olu\u015facak \u0131s\u0131 veren i\u015flemler) dir.
\nKopacak ba\u011flar Olu\u015facak ba\u011flar
\nC = C : 619 kJ C \u2013 C : 348 kJ
\nH \u2013 H : 436 kJ 2(C \u2013 H) : 2 x 413 = 826 kJ
\n1055 kJ -1174 kJ
\nTepkimenin enerji de\u011fi\u015fimi, bu iki de\u011ferin toplam\u0131na e\u015fittir:
\n+ 1055 \u2013 1174 = -119 kJ
\n8.3 EKZOTERM\u0130K VE ENDOTERM\u0130K TEPK\u0130MELER
\n\u0130\u00e7 Enerji De\u011fi\u015fmesi, D E
\nBir sistemin toplam enerjisi, bile\u015fenlerinin kinetik ve potansiyel enerjilerinin toplam\u0131na e\u015fittir. \u00d6rne\u011fin 5.1 \u015eekildeki sistemin toplam i\u00e7 enerjisi, o sistemi olu\u015fturan atomlar, molek\u00fcller ve atomalt\u0131 par\u00e7ac\u0131klar aras\u0131ndaki itme ve \u00e7ekme kuvvetleri (potansiyel enerji) ile t\u00fcm sistem par\u00e7ac\u0131klar\u0131n\u0131n kinetik enerjilerini i\u00e7erir. Termodinami\u011fin birinci yasas\u0131na g\u00f6re, yal\u0131t\u0131lm\u0131\u015f bir sistemin i\u00e7 enerjisi sabittir. Herhangi bir sistemin i\u00e7 enerjisinin “ger\u00e7ek” de\u011feri bilinemez. Buna kar\u015f\u0131n kimyasal ve fiziksel s\u00fcre\u00e7lerde i\u00e7 enerjideki “de\u011fi\u015fme” \u00f6l\u00e7\u00fclebilir. \u0130\u00e7 enerjideki de\u011fi\u015fme D E (okunu\u015fu “delta E” dir) ile g\u00f6sterilirse bu, sonu\u00e7taki (E2) ve ba\u015flang\u0131\u00e7taki (E1) enerji fark\u0131na e\u015fittir:
\nD E = E1 \u2013 E2
\nBu ba\u011f\u0131nt\u0131ya g\u00f6re E2 > E1 ise sistem enerji kazanm\u0131\u015ft\u0131r ve D E pozitif i\u015faretli olacakt\u0131r. E2 < E1 ise sistem enerji kaybetmi\u015ftir ve D E negatif i\u015faretli olacakt\u0131r. H2 ve O2nin su olu\u015fturdu\u011fu kimyasal tepkimeyi ele alal\u0131m. Bu tepkime s\u0131ras\u0131nda enerji a\u00e7\u0131\u011fa \u00e7\u0131kt\u0131\u011f\u0131na g\u00f6re H2 ve O2 nin i\u00e7 enerjisi, suyun i\u00e7 enerjisinden daha b\u00fcy\u00fckt\u00fcr.\nBir sistemle \u00e7evresi aras\u0131ndaki enerji de\u011fi\u015fimi, genel olarak iki \u015fekilde olur: Is\u0131 ve i\u015f \u015fekillerinde. Fiziksel ve kimyasal de\u011fi\u015fmeler ge\u00e7iren bir sistemde i\u00e7 enerji de\u011fi\u015fimi ( D E), sistemin \u0131s\u0131 de\u011fi\u015fimi (q) ile i\u015f de\u011fi\u015fiminin (w) toplam\u0131na e\u015fittir.\nD E = q + w\nSisteme, \u0131s\u0131 veya mekanik i\u015f kat\u0131l\u0131yorsa bu terimlerin say\u0131sal de\u011feri art\u0131 i\u015faretli, sistemin \u0131s\u0131 kaybetmesi veya i\u015f yapmas\u0131 halinde ise eksi i\u015faretli olur. \u00d6rne\u011fin bir sistem 200 kJ \u0131s\u0131 al\u0131p bunun 40 kJ\u2019l\u00fck k\u0131sm\u0131n\u0131 mekanik i\u015f harcam\u0131\u015f olsun. Buna g\u00f6re\nq = +200 kJ (sistemin kazand\u0131\u011f\u0131 \u0131s\u0131, art\u0131 i\u015faretli)\nw = \u201340 kJ (sistemin kaybetti\u011fi \u0131s\u0131, eksi i\u015faretli) dir.\nD E = +200 kJ + (\u201340 kJ) = 160 kJ\nEnerji a\u00e7\u0131\u011fa \u00e7\u0131kararak y\u00fcr\u00fcyen tepkimelere ekzotermik tepkimeler denir; bu tip olaylarda sistemin enerjisi azal\u0131r, \u00e7evrenin eerjisi artar. Yanma tepkimeleri ekzotermiktir. \u00c7evreden enerji alarak y\u00fcr\u00fcyen tepkimelere endotermik tepkimeler denir. Bu tip olaylarda ise sistemin enerjisi artar, \u00e7evrenin enerjisi azal\u0131r. Bir molek\u00fcldeki ba\u011flar\u0131n k\u0131r\u0131lmas\u0131 endotermik bir olayd\u0131r.\nEntalpi De\u011fi\u015fmesi, D H\nKimyasal tepkimeler s\u0131ras\u0131ndaki enerji de\u011fi\u015fimi, hacmin ya da bas\u0131nc\u0131n sabit olmas\u0131na g\u00f6re de\u011fi\u015fir. Sabit hacimde (bir \u00e7elik kapta) y\u00fcr\u00fcyen bir tepkimede \u00e7evreye kar\u015f\u0131 bir i\u015f yapma ya da \u00e7evreden i\u015f alma eylemi olmaz. Bu durumda D E = q + w ba\u011f\u0131nt\u0131s\u0131nda w = 0 olur. Hacmin de\u011fil de bas\u0131nc\u0131n sabit tutuldu\u011fu ko\u015fullarda, hacim de\u011fi\u015fmesi (D V) olabilir. Bilindi\u011fi gibi bas\u0131n\u00e7, birim y\u00fczeyde dik olarak etkiyen kuvvettir. P = F\/A. Pistonlu bir gaz kab\u0131ndaki gaz\u0131 \u0131s\u0131tal\u0131m. Is\u0131nan gaz genle\u015fir. 1.5 \u015eekildeki gibi piston V1 konumundan V2 konumuna ge\u00e7er; yani DV kadar hacim de\u011fi\u015fmesi olur. Is\u0131nan gazda q art\u0131 i\u015faretlidir. Ancak pistonun yukar\u0131 \u00e7\u0131k\u0131\u015f\u0131 i\u00e7in yap\u0131lan i\u015f (P x D V) eksi i\u015faretlidir. Buna g\u00f6re i\u00e7 enerjideki de\u011fi\u015fme \u015f\u00f6yledir:\nD E = q + w = q \u2013 PxD V\nSabit bas\u0131n\u00e7taki i\u00e7 enerji de\u011fi\u015fimini veren bu denklem\nq = D E + Px D V (sabit bas\u0131n\u00e7ta)\nbi\u00e7iminde de yaz\u0131labilir. \u0130\u015fte sabit bas\u0131n\u00e7ta, bir sistemin i\u00e7 enerjisindeki art\u0131\u015fla bas\u0131n\u00e7-hacim i\u015finin toplam\u0131ndan olu\u015fan \u0131s\u0131 de\u011fi\u015fimine, entalpi de\u011fi\u015fimi (D H) denir.\nq = D E + Px D V = D H\nEntalpi de\u011fi\u015fimi (D H) = Sabit bas\u0131n\u00e7taki enerji de\u011fi\u015fimi (D H = qp (sabit bas\u0131n\u00e7ta)\n5.3 \u00d6RNEK\nSodyum metalinin su ile tepkimesinde sodyum hidroksit \u00e7\u00f6zeltisi ve hidrojen gaz\u0131 olu\u015fur.Bu tepkimede 2 mol sodyum i\u00e7in i\u00e7 enerji de\u011fi\u015fimi \u2013370 kJ;bas\u0131n\u00e7 hacim i\u015fi i\u00e7in de 2.5 kJ enerji harcanm\u0131\u015ft\u0131r. Tepkimenin entalpi de\u011fi\u015fimini hesaplay\u0131n\u0131z\n\u00c7\u00f6z\u00fcm\nTepkime \u015fudur:\n2Na (k)+ 2H2O (s) \u00be \u00ae 2NaOH (aq)+ H2(g)\nBu tepkimede a\u00e7\u0131\u011fa \u00e7\u0131kan hidrojen gaz\u0131, bas\u0131nc\u0131 sabit tutmak i\u00e7in d\u0131\u015far\u0131ya kar\u015f\u0131 i\u015f yapar (pistonu yukar\u0131 iter):\nD H =D E + P x D V = -370+2.5= -367.5 kJ olur.\nEntalpi kavram\u0131n\u0131n karakteristik \u00f6zellikleri a\u015fa\u011f\u0131daki gibi \u00f6zetlenebilir:\n1. Entalpi de\u011fi\u015fmesi, \u00fcr\u00fcnlerle girenlerin entalpilerinin fark\u0131na e\u015fittir:\nD H =S H (\u00fcr\u00fcnler) \u2013 S H (girenler)\n\u00dcr\u00fcnlerin entalpisi girenlerinkinden b\u00fcy\u00fckse (endotermik tepkime) D H art\u0131, i\u015faretlidir. \u00d6rne\u011fin azot, (N2) ve oksijenden, (O2), azot monoksit, (NO2) olu\u015fmas\u0131 endotermik bir tepkimedir.\nIs\u0131 + N2 (g) + O2 (g) \u00be \u00ae 2NO (g)\nBu tepkime, y\u00fcksek s\u0131cakl\u0131kta havadaki gazlar\u0131n (N2 ve O2) tepkimeye girmesi ya da azotun yanmas\u0131d\u0131r. 1.6 \u015eekilde g\u00f6sterildi\u011fi gibi 2NO (g) nun entalpi i\u00e7eri\u011fi, N2 (g) ve O2 (g) ninkinden b\u00fcy\u00fckt\u00fcr.\n\u00dcr\u00fcnlerin entalpi i\u00e7eri\u011fi girenlerinkinden k\u00fc\u00e7\u00fckse (ekzotermik tepkime), D H eksi i\u015faretli olur. Hidrojen ve oksijen gazlar\u0131ndan su olu\u015fmas\u0131 b\u00f6yle bir tepkimedir. (5.7 \u015eekil inceleyiniz).\n2H2 (g) + O2 (g) \u00be \u00ae 2H2O (g) + \u0131s\u0131\n2. Entalpi, kapsamsal (madde miktar\u0131na ba\u011fl\u0131) bir \u00f6zelliktir.\nKimyasal tepkimelerdeki entalpi de\u011fi\u015fimi, madde miktar\u0131na ba\u011fl\u0131 bir de\u011ferdir. Metan yan\u0131nca, karbondioksit ve su olu\u015fur. Bu tepkimede 1 mol CH4 sabit bas\u0131n\u00e7ta yan\u0131nca 192 Kkal (802 kJ) de\u011ferinde enerji a\u00e7\u0131\u011fa \u00e7\u0131kar.\nCH4 (g) + 2O2 (g) \u00be \u00ae CO2 (g) + 2H2O (g) D H = -802 kJ\nEntalpi de\u011fi\u015fiminin eksi i\u015faretli olmas\u0131, tepkimenin ekzotermik oldu\u011funu g\u00f6sterir. Entalpi de\u011fi\u015fiminin denkle\u015fmi\u015f tepkime i\u00e7in ge\u00e7erli oldu\u011funu belirtelim.\nYani 1 mol CH4, 2 mol O2 (g) ile tam olarak yan\u0131p, 1 mol CO2 (g) ve 2 mol H2O (g) olu\u015ftururken 802 kJ enerji a\u00e7\u0131\u011fa \u00e7\u0131kar. E\u011fer 2 mol CH4, 4 mol O2 ile yanarsa 2 x 802 = 1604 kJ enerji a\u00e7\u0131\u011fa \u00e7\u0131kacakt\u0131r.\n2CH4 (g) + 4O2 (g) \u00be \u00ae 2CO2 (g) + 4H2O (g) D H\u00b0 = -1604 kJ\n8.4 \u00d6RNEK\nA\u015fa\u011f\u0131daki tepkimeye g\u00f6re 3.6 g suyun elementlerine ayr\u0131\u015fmas\u0131 s\u0131ras\u0131ndaki entalpi de\u011fi\u015fimi ka\u00e7 kJ\u2019dir?\nH2O (s) \u00be \u00ae H2 (g) + 1\/2 O2 (g) D H\u00b0 = 285.8 kJ\/mol\n\u00c7\u00f6z\u00fcm\nVeriye g\u00f6re 1 mol s\u0131v\u0131 su (18 g H2O) nun elementlerine ayr\u0131\u015fmas\u0131 i\u00e7in 285.8 kJ entalpi de\u011fi\u015fimi oluyor.\n285.8 kJ\/mol\n\u00a5\u00a5\u00a5\u00a5\u00a5\u00a5\u00a5 x 3,6 g = 57.16 kJ enerji gerekir.\n18 g\/mol\n* Kuvvetli asit ve kuvvetli baz tepkimeleri ekzotermiktir:\nH+ (aq) + OH\u2013 (aq) \u00be \u00ae H2O (s) D H\u00b0 = \u201357 kJ\n8.5 \u00d6RNEK\nAmonyum nitrat a\u015fa\u011f\u0131daki tepkimeye g\u00f6re patlayarak ayr\u0131\u015f\u0131r:\nNH4NO3 (k) \u00be \u00ae N2O (g) + 2H2O (g) D H\u00b0 = \u20138.9 Kkal\nSabit bas\u0131n\u00e7ta 0.05 mol amonyum nitrat\u0131n ayr\u0131\u015fmas\u0131yla a\u00e7\u0131\u011fa \u00e7\u0131kacak \u0131s\u0131, ka\u00e7 Kkal dir?\n\u00c7\u00f6z\u00fcm\n1 mol amonyum nitrat ayr\u0131\u015ft\u0131\u011f\u0131nda 8.9 Kkal a\u00e7\u0131\u011fa \u00e7\u0131kt\u0131\u011f\u0131na g\u00f6re\n0.05 mol x 8.9 Kkal\/mol = 0.445 Kkal \u0131s\u0131 a\u00e7\u0131\u011fa \u00e7\u0131kar.\n* Demir (III) oksit ve al\u00fcminyum tozu kar\u0131\u015f\u0131m\u0131, termit tepkimesi olarak adland\u0131r\u0131lan \u015fiddetli bir tepkime verir. Termit tepkimesi, b\u00fcy\u00fck demir aksamlar\u0131 (demir yolu raylar\u0131 gibi), yerinde kaynak yaparak birle\u015ftirmek i\u00e7in kullan\u0131l\u0131r, ekzotermik bir tepkimedir.\n8.5 \u00d6RNEK\nA\u015fa\u011f\u0131daki tepkimeye g\u00f6re 0.2 mol Al ile 0.3 mol O2 \u2018in etkile\u015fmesiyle ka\u00e7 kJ a\u00e7\u0131\u011fa \u00e7\u0131kar?\n4 Al (k) + 3O2 (g) \u00be \u00ae 2Al2O3 (k) D H\u00b0 = \u20133352 kJ\n\u00c7\u00f6z\u00fcm\nTepkimeye g\u00f6re 0.3 mol O2, 0.4 mol Al ile tepkimeye girer; Al daha az verildi\u011fine g\u00f6re Al tepkimeyi s\u0131n\u0131rlar. Ba\u015fka deyi\u015fle 0.2 mol Al, 0.15 mol O2 ile birle\u015fir. 4 mol Al tepkimeye girseydi 3352 kJ a\u00e7\u0131\u011fa \u00e7\u0131kacakt\u0131.\n3352 kJ\n\u00a5\u00a5\u00a5\u00a5 x 0.2 mol Al = 167.6 kJ enerji a\u00e7\u0131\u011fa \u00e7\u0131kar.\n4 mol Al\n3. Bir tepkime ters \u00e7evrilirse D H, i\u015faret de\u011fi\u015ftirir:\nDo\u011fald\u0131r ki, ekzotermik bir tepkime ters \u00e7evrilirse endotermik olur; endotermik tepkime ters \u00e7evrilirse ekzotermik olur.\nCH4 (g) + 2O2 (g) \u00be \u00ae CO2 (g) + 2H2O (g) D H\u00b0 = \u2013 802 kJ\/mol\nMetan\u0131n yanma tepkimesini tersinden yazarsak\nCO2 (g) + 2H2 (g) \u00be \u00ae CH4 (g) + 2O2 (g) D H\u00b0 = + 802 kJ\/mol elde ederiz.\n4. Bir t epkimenin entalpi de\u011fi\u015fimi, \u00fcr\u00fcnlerin ve tepkimeye girenlerin hallerine ba\u011fl\u0131d\u0131r.\n\u00d6rne\u011fin metan\u0131n yanma tepkimesindeki entalpi de\u011fi\u015fimi, H2O nun gaz veya s\u0131v\u0131 olmas\u0131na g\u00f6re de\u011fi\u015fir. H2O nun gaz hali i\u00e7in 192 Kkal enerji a\u00e7\u0131\u011fa \u00e7\u0131karken, s\u0131v\u0131 hali i\u00e7in 213 Kkal enerji a\u00e7\u0131\u011fa \u00e7\u0131kar (Gaz\u0131n yo\u011funla\u015fmas\u0131 nedeniyle enerji a\u00e7\u0131\u011fa \u00e7\u0131kaca\u011f\u0131n\u0131 an\u0131msay\u0131n\u0131z).\n2H2O (g) \u00be \u00ae 2H2O (s) D H\u00b0 = \u201387 kJ\/mol\n\u00dcr\u00fcnlerin ve tepkimeye girenlerin halleri, bulunduklar\u0131 s\u0131cakl\u0131\u011fa ba\u011fl\u0131d\u0131r. Kullan\u0131lan entalpi de\u011fi\u015fimleri, genel olarak 250C deki de\u011ferlerdir. 250C ve 1 atm bas\u0131n\u00e7 ko\u015fullar\u0131ndaki de\u011ferlere standart tepkime entalpileri %entalpi de\u011fi\u015fimleri) denir. Standart entalpi de\u011fi\u015fimleri DH0 \u015feklinde g\u00f6sterilir.\n8.4 OLU\u015eMA ENTALP\u0130LER\u0130\nTepkime entalpisi, tepkimenin niteli\u011fine g\u00f6re belirtilebilir: Olu\u015fma entalpisi,yanma entalpisi, \u00e7\u00f6z\u00fcnme entalpisi, n\u00f6t\u00fcrle\u015fme entalpisi, ba\u011f entalpisi gibi... Bunlar i\u00e7inde \u00f6zellikle olu\u015fum entalpileri iyi kavranmal\u0131d\u0131r. \u00c7\u00fcnk\u00fc genel olarak tepkime entalpileri, olu\u015fum entalpileriyle bulunur.\nElementlerin standart hallerinin olu\u015fma entalpileri, s\u0131f\u0131r kabul edilir. E\u011fer elementin standart ko\u015fullarda birka\u00e7 allotropu bulunuyorsa bunlar\u0131n en kararl\u0131s\u0131, elementin standart halidir. \u00d6rne\u011fin elmas, grafit ve amorf karbon, karbon elementinin allotroplar\u0131d\u0131r. Bunlar\u0131n en kararl\u0131s\u0131 grafittir ve onun olu\u015fum entalpisi s\u0131f\u0131r al\u0131n\u0131r. Elmas\u0131n olu\u015fum entalpisi s\u0131f\u0131r de\u011fildir (5.2 Tablo).\nC (grafit) \u00be\u00ae C (elmas) D H\u00b0 = 1.9 kJ\/mol\n\u00c7\u00f6zeltilerde ve iyonlar aras\u0131 tepkimelerde, hidrojen iyonunun (H+) olu\u015fum entalpisi s\u0131f\u0131r al\u0131nm\u0131\u015ft\u0131r.\nBile\u015fiklerin olu\u015fma entalpisi, o bile\u015fi\u011fin standart, ko\u015fullardaki elementlerinden olu\u015fumu s\u0131ras\u0131ndaki entalpi de\u011fi\u015fimidir. \u00d6rne\u011fin kalsiyum karbonat\u0131n,CaCO3 (k), standart olu\u015fum entalpisi denince, onu olu\u015fturan elementlerin, 25oC ve 1 atm\u2019deki fiziksel durumlar\u0131 d\u00fc\u015f\u00fcn\u00fclerek, \u015fu denklemin entalpisi (1 mol CaCO3) anla\u015f\u0131l\u0131r:\nCa(k) + C(k) + 3\/2 O2(g) \u00be\u00ae CaCO3 (k) D H\u00b0 = \u2013 1205 kJ\/mol\nOlu\u015fma entalpileri, o bile\u015fiklerin \u0131s\u0131 kar\u015f\u0131s\u0131nda ne derece kararl\u0131 oldu\u011funu bildirir. \u00d6rne\u011fin Al2O3 (k) \u00fcn olu\u015fum entalpisi \u20131676 kJ\/mol; B2O3 (k) \u00fcn olu\u015fum entalpisi \u20131262 kJ\/mol; CO2 (g)'nin \u2013393.5 kJ\/mol ve NO (g) nun +90.3 kJ\/mol verileri, Al2O3 (k) \u00fcn \u0131s\u0131sal bak\u0131mdan \u00e7ok kararl\u0131 (\u00e7ok d\u00fc\u015f\u00fck enerjili) oldu\u011funu ve y\u00fcksek s\u0131cakl\u0131klarda bozunabilece\u011fini g\u00f6sterir. 5.2 Tabloda standart olu\u015fum entalpileri kJ\/mol birimiyle veriliyor. 5.9 \u015eekilde baz\u0131 bile\u015fiklerin olu\u015fum entalpileri kar\u015f\u0131la\u015ft\u0131r\u0131l\u0131yor. Bir bile\u015fi\u011fin olu\u015fumu s\u0131ras\u0131nda a\u00e7\u0131\u011fa \u00e7\u0131kan enerji ne kadar b\u00fcy\u00fckse, o bile\u015fik \u0131s\u0131sal bak\u0131mdan o derece kararl\u0131d\u0131r.\n\n8.6 \u00d6RNEK\nBaz\u0131 bile\u015fiklerin standart molar ou\u015fum entalpileri \u015f\u00f6yledir (kJ\/mol):\nAl2O3 (k): \u20131672; KClO3 (k): \u2013390; N2O (g): 81\nEntalpi de\u011fi\u015fimlerini (D H\u00b0 ) de g\u00f6stererek tepkime denklemlerini yaz\u0131n\u0131z.\n\u00c7\u00f6z\u00fcm\nVerilen entalpi de\u011fi\u015fimleri 25oC ve 1 atm ko\u015fullar\u0131ndaki de\u011ferlerdir. Bu ko\u015fullarda al\u00fcminyum (Al) kat\u0131; oksijen gaz (O2); potasyum (K) kat\u0131; klor gaz (Cl2) ve azot gaz (N2) halindedir. Buna g\u00f6re tepkimeleri a\u015fa\u011f\u0131daki gibi yazabiliriz:\n2Al (k) + 3\/2 O2 (g) \u00be\u00ae Al2O3 (k) D H\u00b0 = \u20131672 kJ\/mol\nK (k) + 1\/2 Cl2 (g) + 3\/2 O2 (g) \u00be\u00ae KClO3 (k) D H\u00b0 = -390 kJ\/mol\nN2 (g) + O2 \u00be\u00ae N2O (g) D H\u00b0 = +81 kJ\/mol\n8.7 \u00d6RNEK\nAl\u00fcminyum s\u00fclfat\u0131n, Al2(SO4)3, standart molar olu\u015fum entalpisi \u20133440 kJ\u2019dir. Bu tepkimeyi a\u015fa\u011f\u0131dakilerden hangisi g\u00f6sterir?\nI. 2Al+3 (aq) + 3SO4-2 (aq) \u00be \u00ae Al2(SO4)3 (k) + 3440 kJ\nII. Al2O3 (k) + 3SO3 (g) \u00be \u00ae Al2(SO4)3 (k) + 3440 kJ\nIII. 2 Al (k) + 3H2SO4 (aq) \u00be \u00ae Al2(SO4)3 (k) + 3H2 (g) + 3440 kJ\nIV. 2 Al (k) + 3S (k) + 6 O2 (g) \u00be \u00ae Al2(SO4)3 (k) + 3440 kJ\nAl\u00fcminyum s\u00fclfat\u0131n standart ko\u015fullardaki elementleri Al (k), S (k) ve O2 (g) oldu\u011fu i\u00e7in IV. tepkime onun olu\u015fum tepkimesidir.\n8.8 \u00d6RNEK\nSO2 (g) ve SO3 (g) maddelerinin standart olu\u015fum entalpileri s\u0131rayla \u2013296 kJ\/mol ve \u2013394 kJ\/mol d\u00fcr. Buna g\u00f6re a\u015fa\u011f\u0131daki tepkimenin entalpisi ka\u00e7 kJ\u2019 dir?\n2SO2 (g) + O2 (g) \u00be \u00ae 2SO3 (g)\n\u00c7\u00f6z\u00fcm\nOlu\u015fum entalpilerine ba\u011fl\u0131 olarak tepkimenin entalpi de\u011fi\u015fimi, \u00fcr\u00fcnlerle girenlerin entalpi de\u011fi\u015fimleri fark\u0131na e\u015fittir.\nD H =S H (\u00fcr\u00fcnler) \u2013 S H (girenler)\n2SO2 + O2 \u00be \u00ae 2SO3\n2(\u2013296) 0 2 (\u2013394)\nD H\u00b0 = (\u2013788) \u2013 (\u2013592) = \u2013196 kJ \n8.5 YANMA ENTALP\u0130LER\u0130\nYanma, bir maddenin \u0131\u015f\u0131k ve \u0131s\u0131 enerjileri yayarak oksijenle birle\u015fmesidir.Yanma olay\u0131, enerji yayan (ekzotermik) bir kimyasal tepkimedir. Bir mol maddenin yanmas\u0131 ile a\u00e7\u0131\u011fa \u00e7\u0131kan enerjiye, molar yanma \u0131s\u0131s\u0131 (entalpisi) denir. \u00d6rne\u011fin metan (CH4) i\u00e7in molar yanma entalpisi \u2013802 kJ\u2019 d\u00fcr ve tepkimesi \u015f\u00f6yledir:\nCH4 (g) + 2O2 (g) \u00be \u00ae CO2 (g) + 2H2O (g) D H\u00b0 = -802 kJ\/mol\n8.9 \u00d6RNEK\n1 g s\u0131v\u0131 benzen, C6H6 yan\u0131nca 42 kJ \u0131s\u0131 a\u00e7\u0131\u011fa \u00e7\u0131kar.\n(a) Benzenin molar yanma entalpisini g\u00f6steren denklemi yaz\u0131n\u0131z. (C6H6 : 78 g\/mol)\n(b) Tepkime \u00fcr\u00fcnleri CO2 (g) ve H2O (s) i\u00e7in molar olu\u015fum entalpileri s\u0131rayla ve oldu\u011funa g\u00f6re benzenin olu\u015fum entalpisi ka\u00e7?\n\u00c7\u00f6z\u00fcm\n(a) 1 g benzen yan\u0131nca 42 kJ enerji verdi\u011fine g\u00f6re 78 g benzen (1 mol benzen) yan\u0131nca\n42 kJ x 78 g C6H6 = 3276 kJ a\u00e7\u0131\u011fa \u00e7\u0131kar. Buna g\u00f6re tepkimeyi a\u015fa\u011f\u0131daki gibi yazabiliriz:\nC6H6 (s) + 15\/2 O2 (g) \u00be\u00ae 6CO2 (g) + 3H2O (s) D H\u00b0 = -3276 kJ\n(b) D H\u00b0 = H\u00fcr \u2013 Hgir ba\u011f\u0131nt\u0131s\u0131na g\u00f6re\nC6H6 (s) + 15\/2 O2 (g) \u00be\u00ae 6CO2 (g) + 3H2O (s)\n(x) 0 6(\u2013394) 3(\u2013286)\nD H\u00b0 = 6 (-394) + 3 (-286) \u2013 (x) = - 3276 kJ\u2019den x = + 54 kJ bulunur. S\u0131v\u0131 benzenin molar olu\u015fum entalpisi, + 54 kJ yani;\n6C (k) + 3H2(g) \u00be\u00ae C6H6 (s) DH\u00b0 = +54 kJ\u2019 dir.\nYanma entalpileri 5.11 \u015fekilde g\u00f6sterilen kalorimetrelerde \u00f6l\u00e7\u00fcl\u00fcr.\n8.10 \u00d6RNEK\nBaz\u0131 olu\u015fum entalpileri \u015f\u00f6yledir\nCH3OH (s) : -239 kJ\/mol ,CO2 (g) : -394 kJ\/mol, H2O (g) : -242 kJ\/mol\noldu\u011funa g\u00f6re metanol, CH3OH, i\u00e7in molar yanma entalpisi ka\u00e7 kJ\u2019dir?\n\u00c7\u00f6z\u00fcm\nYanma tepkimesini yaz\u0131p denkle\u015ftirdikten sonra,ilgili maddelerin ou\u015fum entalpilerini altlar\u0131na yazal\u0131m:\nCH3 OH(s) + 3\/2 O2 (g) \u00be \u00ae CO2 (g) + 2H2O (g)\n(-239) (0) (-394) 2(-242)\nTepkime entalpileri \u00fcr\u00fcnlerle girenlerin entalpileri fark\u0131na e\u015fit oldu\u011fundan\nD H\u00b0 = H\u00fcr \u2013Hgir =2 (-242) + (-394) \u2013 (-239) = -639 kJ sonucu elde edilir.\nBu sonu\u00e7, CH3 OH(s) n\u0131n bir mol\u00fc yan\u0131nca a\u00e7\u0131\u011fa \u00e7\u0131kan enejiyi g\u00f6stermektedir.\n8.6 ENTALP\u0130 DE\u011e\u0130\u015e\u0130MLER\u0130N\u0130N TOPLANAB\u0130L\u0130RL\u0130\u011e\u0130 Hess Yasas\u0131\nEntalpi, tan\u0131m olarak enerjinin iki bi\u00e7iminin, \u0131s\u0131 ile mekanik i\u015fin toplam\u0131d\u0131r. Maddeler toplanabiliyorsa, onlar\u0131n enerjileri de toplanabilir. Bu denel sonu\u00e7, entalpi de\u011fi\u015fimlerine de uygulanabilir. 1 mol CH4 (g), 2 mol O2 (g) ile yan\u0131p 1 mol CO2 (g) ve 2 mol H2O (g) verince 802 kJ \u0131s\u0131 a\u00e7\u0131\u011fa \u00e7\u0131kar. Bu tepkimedeki entalpi de\u011fi\u015fimini suyun s\u0131v\u0131 hali i\u00e7in bulmak \u00fczere a\u015fa\u011f\u0131daki i\u015flemi yapmal\u0131y\u0131z:\nCH4 (g) 2O2 (g) \u00be\u00ae CO2 (g) + 2H2O(g) DH\u00b0 = -802 kJ\n2H2O (g) \u00be\u00ae 2H2O (s) DH\u00b0 = -88 kJ\nCH4 (g) + 2O2 (g) \u00be\u00ae CO2 (g) + 2H2O (s) DH\u00b0 = -890 kJ\nBir tepkime, bir tepkime dizisi sonucunda elde edilebiliyorsa onun entalpi de\u011fi\u015fimi, dizilerin entalpi de\u011fi\u015fimlerinin toplam\u0131na e\u015fittir. Bu sonu\u00e7, 1840\u2019da Alman kimyac\u0131 G. Hess taraf\u0131ndan bulundu. Hess Yasas\u0131 diye an\u0131lan bu yasaya g\u00f6re, bir tepkime ister tek bir ad\u0131mda, ister \u00e7ok de\u011fi\u015fik ad\u0131mlar izleyerek sonu\u00e7lans\u0131n, onun D H de\u011feri hep ayn\u0131d\u0131r. Termodinamik, sistemin izledi\u011fi yolu de\u011fil, sonu\u00e7 ve ba\u015flang\u0131\u00e7 hallerini inceler. Buna g\u00f6re Hess yasas\u0131, \u015fu temele dayan\u0131r. Bir tepkimenin entalpi de\u011fi\u015fimi, o tepkimenin izledi\u011fi yola ba\u011fl\u0131 de\u011fildir; sadece son ve ilk hallere ba\u011fl\u0131d\u0131r. \u00d6rne\u011fin C (k) ve O2 (g) den CO2 (g) olu\u015fumu iki yoldan ger\u00e7ekle\u015febilir. Birinci yol, elementlerden do\u011frudan CO2 (g) olu\u015fumu; ikinci yol elementlerinden, \u00f6nce CO (g) ve sonra CO2 (g) olu\u015fumudur. 5.12 \u015fekli inceleyiniz. \n8.11 \u00d6RNEK\nC (grafit) + O2 (g) \u00be \u00ae CO2 (g) D H\u00b0 = -393.5 kJ\nC (elmas) + O2 (g) \u00be \u00ae CO2 (g) D H\u00b0 = -395.4 kJ\noldu\u011funa g\u00f6re\nC (grafit) \u00be \u00ae C (elmas)\ntepkimesi i\u00e7in D H\u00b0 ka\u00e7 kJ dir?\n\u00c7\u00f6z\u00fcm\nEntalpi de\u011fi\u015fimi sorulan tepkimeyi elde etmek i\u00e7in verilen ilk tepkime ayn\u0131 kalmal\u0131, ikinci ters \u00e7evrilip toplanmal\u0131d\u0131r.\nC (grafit) + O2 (g) \u00be \u00ae CO2 (g) D H\u00b0 = -393.5 kJ\nCO2 (g) \u00be \u00ae C (elmas) + O2 (g) D H\u00b0 = +395.4 kJ\nC (grafit) \u00be \u00ae C (elmas) DH\u00b0 = +1.9 kJ\n\n8.12 \u00d6RNEK\nA\u015fa\u011f\u0131daki tepkimeler yoluyla\n2 C (k) + H2 (g) \u00be \u00ae C2H2 (g)\ntepkimesinin D H\u00b0 de\u011ferini hesaplay\u0131n\u0131z.\nC2H2 (g) + 5\/2O2 (g) \u00be \u00ae 2CO2 (g) + H2O (g) DH\u00b0 = - 1256 kJ\nC (k) + O2 (g) \u2013\u00be \u00ae CO2 (g) DH\u00b0 = -393.5 kJ\nH2 (g) + 1\/2 O2 (g) \u00be \u00ae H2O (g) DH\u00b0 = -242 kJ\n\u00c7\u00f6z\u00fcm\nC2H2, \u00fcr\u00fcn konumunda olmas\u0131 gerekti\u011finden verideki ilk tepkime ters \u00e7evrilecektir. C (k) ve H2 (g) giren konumunda bulundu\u011fu i\u00e7in ikinci ve \u00fc\u00e7\u00fcnc\u00fc tepkimeler ayn\u0131 kalacakt\u0131r. Ancak 2C (k) eldesi ve CO2 lerin birbirini g\u00f6t\u00fcrmesi i\u00e7in ikinci tepkime 2 ile \u00e7arp\u0131lmal\u0131d\u0131r.\n1. tepkime ters \u00e7evrilince D H\u00b0 = +1256 kJ\n2. tepkime iki ile \u00e7arp\u0131l\u0131nca D H\u00b0 = -787 kJ\n3. tepkime ayn\u0131 kal\u0131nca D H\u00b0 = -242 kJ\nTepkimeler ve entalpi de\u011fi\u015fimleri topland\u0131\u011f\u0131nda\n2C (k) + H2 (g) \u00be \u00ae C2H2 (g) D H\u00b0 = +127 kJ\/mol elde edilir.\n8.13 \u00d6RNEK\nA\u015fa\u011f\u0131daki veriler yoluyla kat\u0131 magnezyum hidroksitin olu\u015fum entalpisini hesaplay\u0131n\u0131z.\n2 Mg (k) + O2 (g \u00be \u00ae 2 MgO (k) DH\u00b0 = -1204 kJ\nMgO (k) + H2O(s) \u00be \u00ae Mg(OH)2 (k) DH\u00b0 = -37 kJ\n2H2O (s) \u00be \u00ae 2H2(g) + O2 (g) DH\u00b0 = +572 kJ\nYan\u0131t\nMg (k) + H2 (g) + O2 (g) \u00be \u00ae Mg (OH)2 (k) D H\u00b0 = -220,8 Kkal\/mol\n8.B\u00d6L\u00dcM: KONU DENETLEME SORULARI\n8.1 Enerji ne demektir? Kinetik ve potansiyel enerjiler aras\u0131nda ne fark vard\u0131r?\n8.2 Is\u0131 ve s\u0131cakl\u0131k aras\u0131ndaki ili\u015fki nedir? Bunlar\u0131n birimlerini belirtiniz.\n8.3 A\u015fa\u011f\u0131daki de\u011fi\u015fimlerin hangilerinde enerji a\u00e7\u0131\u011fa \u00e7\u0131kar?\n(a) Su buhar\u0131 yo\u011funla\u015f\u0131rken\n(b) Metan (CH4) gaz\u0131 yanarken\n(c) Uyar\u0131lm\u0131\u015f atom, temel duruma d\u00f6nerken\n(d) H2(g) ve O2(g) den H2O (g) olu\u015furken\n8.4 A\u015fa\u011f\u0131daki tepkimelerden hangilerinin ekzotermik olmas\u0131 beklenir?\n(a) Cl (g) + e- \u00be \u00ae Cl- (g)\n(b) 2Cl (g) \u00be \u00ae Cl2 (g)\n(c) 2H2O (g) \u00be \u00ae 2H2 (g) + O2 (g)\n(d) 2Al (k) + 3\/2 O2 (g) \u00be \u00ae Al2O3 (k)\n(e) Na+ (g) + Cl- (g) \u00be \u00ae NaCl (k)\n8.5 A\u015fa\u011f\u0131daki \u00e7iftlerde, hangisinin d\u00fczensizlik derecesi (entropisi) daha y\u00fcksektir?\n(a) Ayn\u0131 s\u0131cakl\u0131k ve bas\u0131n\u00e7ta 1 mol H2O (g)\n(b) Ayn\u0131 bas\u0131n\u00e7 ve mol say\u0131s\u0131nda 58oC'de Br2 (s) veya \u201310oC'de Br2 (k)\n(c) Ayn\u0131 mol say\u0131s\u0131nda ve s\u0131cakl\u0131kta 0.10 atm O2 (g) veya 10 atm O2 (g)\n8.6 A\u015fa\u011f\u0131daki s\u00fcre\u00e7lerde entalpi de\u011fi\u015fimlerinin i\u015faretini belirtiniz.\n(a) CO2 (k) \u00be\u00ae CO2 (g)\n(b) PCl5 (s) \u00be\u00ae PCl5 (g)\n(c) Hg(s) \u00be\u00ae Hg (k)\n(d) BaCl2 (s) \u00be\u00ae BaCl2 (k)\n8.7 Bir \u015feker olan glukoz, oksijen ile yan\u0131nca karbondioksit ve su verir.\nC6H12O6 (k) + 6O2 (g) \u00be \u00ae 6CO2 (g) + 6H2O (s) D H\u00b0 = -2820 kJ\n(a) 0,02 mol glukoz yan\u0131nca ka\u00e7 kJ a\u00e7\u0131\u011fa \u00e7\u0131kar?\n(b) 0,60 mol glukoz, 0,60 mol O2(g) ile tepkimeye girince en \u00e7ok ka\u00e7 kJ a\u00e7\u0131\u011fa \u00e7\u0131kar?\n8.8 HF (g) \u00fcn standart molar olu\u015fum entalpisini veren denklem a\u015fa\u011f\u0131dakilerden hangisidir?\nI. H (g) + F (g) \u00be\u00ae HF (g)\nII. H+ (g) +F- (g) \u00be\u00ae HF (g)\nIII. 1\/2 H2 (g) + 1\/2 F2 (g) \u00be\u00ae HF (g)\n8.9 Kalsiyum oksit (CaO) kat\u0131s\u0131n\u0131n standart molar olu\u015fum entalpisini veren tepkime denklemi a\u015fa\u011f\u0131dakilerden hangisidir?\nI. Ca+2 (aq) + O-2 (aq) \u00be \u00ae CaO (k)\nII. Ca(k) + H2O (s) \u00be \u00ae CaO (k) + H2 (g)\nIII. Ca(k) + 1\/2 O2 (g) \u00be \u00ae CaO (k)\n8.10 Ca (k) + O2 (g) + H2 (g) \u00be\u00ae Ca (OH)2 (k) tepkimesi i\u00e7in a\u015fa\u011f\u0131dakilerden hangisi do\u011frudur?\nI. Sentez tepkimesidir.\nII. D H\u00b0 > 0 d\u0131r.
\nIII. Ca(OH)2 (k) n\u0131n olu\u015fma tepkimesidir.
\n8.11 Hidrazin, klor gaz\u0131 ile a\u015fa\u011f\u0131daki tepkimeyi verir:
\nN2H4 (s) + 2Cl2 (g) \u00be \u00ae 4HCl (g) +N2 (g) D H\u00b0 = -420 kJ
\n(a) 25,6 g hidrazin bolca klor gaz\u0131 ile tepkimeye girince ka\u00e7 kJ a\u00e7\u0131\u011fa \u00e7\u0131kar?
\n(b) 0,5 mol HCl olu\u015furken ka\u00e7 kJ a\u00e7\u0131\u011fa \u00e7\u0131kar? (N: 14; H: 1)
\n8.12 Standart olu\u015fum entalpileri
\nNH3 (g) : -49 kJ\/mol, HCl (g) : -92 kJ\/mol, NH4 Cl (k) : -315 kJ\/mol
\nverilerine g\u00f6re a\u015fa\u011f\u0131daki tepkime i\u00e7in D H\u00b0de\u011ferini hesaplay\u0131n\u0131z.
\nNH3 (g) + HCl (g) \u00ab NH4Cl (k) D H\u00b0 = ?
\n8.13 Standart olu\u015fum entalpileri
\nCO2 (g) : -394 kJ\/mol, CH4 (g) :-75 kJ\/mol
\nH2O (g) : -242kJ\/mol, C2H6(g) : -85 kJ\/mol
\nH2O (s) : -286 kJ\/mol
\noldu\u011funa g\u00f6re a\u015fa\u011f\u0131daki yanma entalpilerini hesaplay\u0131n\u0131z.
\n(a) CH4 (g) \u00fcn molar yanma entalpisi. \u00dcr\u00fcnler CO2 (g) ve H2O (g)
\n(b) C2H6 (g) n\u0131n molar yanma entalpisi. \u00dcr\u00fcnler CO2 (g) ve H2O (g)
\n8.14, 8.15 ve 8.16 sorulardaki tepkimelerin DH lerini a\u015fa\u011f\u0131daki ba\u011f enerjilerini kullanarak hesaplay\u0131n\u0131z.
\nBa\u011f Ba\u011f enerjisi (kJ\/mol)
\nH \u2013 H 436
\nF \u2013 F 155
\nO = O 494
\nH \u2013 O 463
\nN = N 941
\nN \u2013 H 389
\nH \u2013 F 565
\n8.14 H2 (g) + F2 (g) \u00be \u00ae 2HF (g)
\n8.15 H2 (g) + 1\/2 O2 (g) \u00be \u00ae H2O (g)
\n8.16 N 2 (g) + 3H2 (g) \u00be \u00ae 2NH3 (g)
\n8.17 Cu (k) + Cl2 (g) \u00be\u00ae CuCl2 (k) DH\u00b0 = -206 kJ
\n2 Cu(k) + Cl2 (g) \u00be\u00ae 2 CuCl (k) D H\u00b0 = -36 kJ verilerine g\u00f6re a\u015fa\u011f\u0131daki tepkime i\u00e7in D H\u00b0 de\u011feri ka\u00e7 kJ d\u00fcr?
\nCuCl2 (k) + Cu (k) \u2013\u00be\u00ae 2CuCl (k)
\n5.18 H2 (g) + F22(g) \u00be\u00ae 2HF (g) DH\u00b0 = -542 kJ
\n2H2 (g) + O2 (g) \u00be \u00ae 2H2O (s) D H\u00b0 = -572 kJ verilerine g\u00f6re a\u015fa\u011f\u0131daki tepkime i\u00e7in D H\u00b0 ka\u00e7 kJ dir?
\n2F2 (g) + 2H2O (s) \u00be \u00ae 4HF (g) + O2 (g)
\n5.19 C (grafit) + O2 (g) \u00be \u00ae CO2 (g) D H\u00b0 = -394 kJ
\n2C (grafit) + O2 (g) \u00be \u00ae 2CO (g) D H\u00b0 = -111 kJ
\nverilerine g\u00f6re a\u015fa\u011f\u0131daki tepkime i\u00e7in D H\u00b0ka\u00e7 kJ dir?
\n2CO (g) + O2 (s) \u00be \u00ae 2CO2 (g)
\n8.20 2NO(g) + O2 \u00be\u00ae 2NO2 (g) DH\u00b0 = -173 kJ
\n2N2 (g) + 5O2 (g) + 2H2O (s) \u00be \u00ae 4HNO3 (aq) DH\u00b0 = -255 kJ
\nN2 (g) + O2 (g) \u00be\u00ae 2NO (g) D H\u00b0 = +181 kJ
\noldu\u011funa g\u00f6re a\u015fa\u011f\u0131daki tepkime i\u00e7in D H\u00b0 ka\u00e7 kJ dir?
\n3NO2 (g) + H2O (s) \u00be \u00ae 2HNO3 (aq) + NO (g)
\n8.21 A\u015fa\u011f\u0131daki verilere g\u00f6re kat\u0131 magnezyum hidroksit Mg(OH)2\u2019in molar olu\u015fum entalpisini hesaplay\u0131n\u0131z.
\n2Mg(k)+O2(g) \u00be\u00ae 2MgO(k) DH\u00b0 =-1204 kJ
\nMgO(k)+H2O(s) \u00be\u00ae Mg(OH)2(k) DH\u00b0 = -37 kJ
\n2H2O(s) \u00be\u00ae 2H2 (g)+ O2(g) DH\u00b0 = +572 kJ
\n8.22 Kalsiyum klor\u00fcr\u00fcn suda \u00e7\u00f6z\u00fcnmesi \u015f\u00f6yledir:
\nCaCl2 (k) \u00be \u00ae Ca+2 (aq) + 2Cl- (aq)
\nolu\u015fum entalpileri kJ\/mol
\nCaCl2 (k) : -796
\nCa+2 (aq) : -534
\nCl- (aq) : -167
\noldu\u011funa g\u00f6re;
\n(a) Kalsiyum klor\u00fcr\u00fcn \u00e7\u00f6z\u00fcnme entalpisini hesaplay\u0131n\u0131z.
\n(b) 22.2 g CaCl2 0,1 L 20oC deki suya eklense s\u0131cakl\u0131k ka\u00e7 derece olur? (100 g su i\u00e7in \u0131s\u0131 kapsam\u0131 418 JK-1 dir.)
\n(c) Ca+2 (aq) + 2Cl- \u00be\u00ae CaCl2 (k) D H\u00b0 = ?<\/p>\n","protected":false},"excerpt":{"rendered":"
Giri\u015f Enerjinin korunumunu ve d\u00f6n\u00fc\u015f\u00fcm\u00fcn\u00fc inceleyen bilim koluna termodinamik denir( Termodinamik ad\u0131, Grek\u00e7e “therme” (\u0131s\u0131) ve “dynamis” (i\u015f) s\u00f6zc\u00fcklerinden t\u00fcretilmi\u015ftir). Bu bilim kolu 19. y\u00fczy\u0131ldaki End\u00fcstri Devrimine ba\u011fl\u0131 olarak do\u011fmu\u015f, \u0131s\u0131 makinalar\u0131n\u0131n verimini artt\u0131rmak i\u00e7in yap\u0131lan \u00e7al\u0131\u015fmalar, \u0131s\u0131, i\u015f ve yak\u0131tlar\u0131n \u0131s\u0131 i\u00e7eri\u011fi kavramlar\u0131n\u0131 \u00f6ne \u00e7\u0131karm\u0131\u015ft\u0131r. Bu bilim kolu, 1920lerde geli\u015ftirilen yeni kuantum kuram\u0131 \u0131\u015f\u0131\u011f\u0131nda …<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1407,1403],"tags":[2168,2167,2136,2166,2162,2164,2165,2163],"class_list":["post-741","post","type-post","status-publish","format-standard","hentry","category-fen-ve-teknoloji-odevleri","category-odevler","tag-aluminyum-sulfat","tag-amonyum-nitrat","tag-hidrojen","tag-kalori","tag-kimyasal-tepkimeler-ve-enerji","tag-oksijen","tag-si","tag-termodinamik"],"_links":{"self":[{"href":"https:\/\/www.islamidavet.com\/kutuphane\/wp-json\/wp\/v2\/posts\/741","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.islamidavet.com\/kutuphane\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.islamidavet.com\/kutuphane\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.islamidavet.com\/kutuphane\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.islamidavet.com\/kutuphane\/wp-json\/wp\/v2\/comments?post=741"}],"version-history":[{"count":0,"href":"https:\/\/www.islamidavet.com\/kutuphane\/wp-json\/wp\/v2\/posts\/741\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.islamidavet.com\/kutuphane\/wp-json\/wp\/v2\/media?parent=741"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.islamidavet.com\/kutuphane\/wp-json\/wp\/v2\/categories?post=741"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.islamidavet.com\/kutuphane\/wp-json\/wp\/v2\/tags?post=741"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}