Chmial Ratins and Equatins Hwitt/Lyns/Suhki/Yh Cnptual Intgratd Sin During a hmial ratin, n r mr nw mpunds ar frmd as a rsult f th rarrangmnt f atms. Chaptr 13 CHEMICAL REACTIONS Ratants Prduts Chmial Ratins and Equatins Aid Bas Ratins Law f Mass Cnsrvatin: N atms ar gaind r lst during any ratin. Th numbr f tims atms appar bfr th arrw must b qual t th numbr f tims thy appar aftr th arrw. Aids Aid Bas Ratins Aid Bas Ratins Aid A hmial that dnats a hydrgn in, H Bas A hmial that apts a hydrgn in, H Bass 1
Th hydrgn atm Th hydrgn in H H B a s A p t s A i d D n a t s HCl H Cl 2 O H 3 O HCl H Cl 2 O H 3 O HCl H Cl 2 O H 3 O d n r a p t r (aid) (bas) 2
H OH 2 O NH 3 H OH 2 O NH 3 d n r a p t r H OH 2 O NH 3 H 2 O NH 3 OH (aid) (bas) (bas) (aid) H OH 2 O NH 3 Salts Salt: An ini mpund frmd frm th ratin f an aid and a bas. (aid) (bas) (bas) (aid) 3
Salts Salt: An ini mpund frmd frm th ratin f an aid and a bas. Salts Salt: An ini mpund frmd frm th ratin f an aid and a bas. Slutins: Aidi, Basi, r Nutral Watr an bhav as an aid r a bas. Slutins: Aidi, Basi, r Nutral Watr an bhav as an aid r a bas. In pur watr, fr vry n hydrnium in, H 3 O, frmd, thr is a hydrxid in, OH, frmd. Slutins: Aidi, Basi, r Nutral Slutins: Aidi, Basi, r Nutral S, in pur watr, [H 3 O ] = [OH ] = 0.0000001 M = 10 7 M. Add hydrnium ins, H 3 O, and th slutin is aidi. Add hydrxid ins, OH, and th slutin is basi. 4
Th ph Sal ph is a masur f th nntratin f hydrnium ins, H 3 O. ph = lg [H 3 O ] Fr pur watr: ph = lg (10 7 ) ph = ( 7) ph = 7 Th ph Sal Th lg f a numbr is simply th pwr t whih tn is raisd. Th lg f 10 3, fr xampl, is 3. Quiz Tim What is th lg f 10 2? Lg 10 2 = 2 (th pwr t whih 10 is raisd) Th ph Sal ph = lg [H 3 O ] Th ph Sal ph = lg [H 3 O ] Fr aidi watr ph < 7, fr xampl: ph = lg (10 5 ) ph = ( 5) ph = 5 Fr basi watr ph > 7, fr xampl: ph = lg (10 9 ) ph = ( 9) ph = 9 Th ph Sal Intgratd Sin Earth Sin Aid Rain 5
Oxidatin-Rdutin Ratins Aid Bas ratins: transfr f prtn Oxidatin-Rdutin Ratins Oxidatin: Th lss f an ltrn Oxidatin-Rdutin ratins: transfr f ltrn 2 Na 2 Na 2 Rdutin: Th gain f an ltrn Cl 2 2 2 Cl L Gr Oxidatin-Rdutin Ratins Oxidatin-Rdutin Ratins 2 Na Cl 2 2 Na 2 Cl Oxidatin-Rdutin Ratins Crrsin and Cmbustin Crrsin: Th prss whrby a mtal dtrirats thrugh xidatin-rdutin ratins. 6
Crrsin and Cmbustin Crrsin an b prvntd by ating th mtal with zin, whih xidizs first. Crrsin and Cmbustin Cmbustin: An xidatin-rdutin ratin btwn a nnmtalli matrial, suh as wd, and xygn. Ratin Rats Ratin rat: Th spd with whih prduts frm frm th ratants. Afftd by Cnntratin Tmpratur Catalyst Prmis: Ratant mluls hav t mak physial ntat with ah thr in rdr t transfrm int prduts. Afftd by Cnntratin Ratin Rats Th mr nntratd a sampl f nitrgn and xygn, th gratr th liklihd that N 2 and O 2 mluls will llid and frm nitrgn mnxid. Afftd by Tmpratur Ratin Rats Afftd by Catalysts Ratin Rats Slw-mving mluls may llid withut nugh fr t brak th bnds. In this as, thy annt rat t frm prdut mluls. Ratant mluls must gain a minimum amunt f nrgy, alld th ativatin nrgy, E at, in rdr t transfrm int prdut mluls. 7
Afftd by Catalysts Ratin Rats Ex- and Endthrmi Ratins Exthrmi ratin: A hmial ratin that rsults in th nt prdutin f nrgy. ratants prduts nrgy Endthrmi ratin: A hmial ratin in whih thr is a nt nsumptin f nrgy. A atalyst has th fft f lwring th ativatin nrgy, whih allws fr th ratin t prd at a quikr rat. nrgy ratants prduts Ex- and Endthrmi Ratins Us th bnd nrgis blw t dtrmin whthr th fllwing ratin is xthrmi r ndthrmi: H 2 Cl 2 2 HCl H-H (bnd nrgy: 436 kj/ml) Cl-Cl (bnd nrgy: 243 kj/ml) H-Cl (bnd nrgy: 431 kj/ml) A. Exthrmi with mr than 50 kj f nrgy rlasd. B. Endthrmi with mr than 50 kj f nrgy absrbd. C. Endthrmi with lss than 50 kj f nrgy absrbd. D. Exthrmi with lss than 50 kj f nrgy rlasd. [Dfault] Entrpy and Chmial Ratins It is th natural tndny f nrgy t disprs frm whr it is nntratd t whr it is dilut. Exampls A ht pan radiats hat Gaslin mbusts int smallr mluls Marbls buning n th flr m t a stp Entrpy and Chmial Ratins It is th natural tndny f nrgy t disprs frm whr it is nntratd t whr it is dilut. Entrpy: Th trm usd t dsrib th dgr t whih nrgy has bm disprsd. Ratins that rsult in an inras in ntrpy (nrgy disprsal) tnd t ur n thir wn. 8
Entrpy and Chmial Ratins Exthrmi ratins tnd t b slf-sustaining baus thy lad t larg inrass in ntrpy. Exampl: A ampfir Endthrmi ratins tnd t rquir th ntinual input f nrgy. Exampl: Phtsynthsis 9